At ISO 400,000, This 6-Minute Film Shows Why We Love the Night Sky

The pursuit of the night sky is ongoing for amateur astronomers. Credit and copyright: Ben Canales.

Obviously, you’ve seen timelapse videos of the night sky because we share them here on Universe Today all the time. But you’ve probably not seen a video like this one before. This one isn’t a timelapse, and you’ll see the night sky in all its splendor, in real time.

“I think this one may be the beginning of something damn interesting,” said filmmaker Ben Canales, who along with cohort John Waller of Uncage The Soul Productions, shot this video with new low-light technology. Using the new Canon MH20f-SH, which has the capability of shooting at 400,000 ISO, they were able to “film in the quiet moments that have been impossible to capture until now.”

“Since 2013, I’ve been tinkering with all sorts of camera/lens/software combinations trying to move beyond a long exposure still to real time video of the stars,” Canales said on Facebook. “Sooner or later, we have to move beyond a frozen photo of the stars to hear, see, feel what it is really like being out there!”

In addition to showcasing this wonderful new low-light shooting, Infinity² really captures the emotional side of amateur astronomy and the beauty of being under the night sky. He took a group of high school students out to witness the Perseid Meteor Shower in Oregon, and the students got together with the Oregon Star Party. Together, they answer the simple question “What do you feel?”

As Canales says, “Something internal and personal draws us out to the night sky.”

Check out more on Uncage The Soul Productions, Canales’ astrophoto website and Facebook.

Still image from the film Infinity ². Image Courtesy Ben Canales.
Still image from the film Infinity². Image Courtesy Ben Canales.
Still image from the film Infinity ². Image Courtesy Ben Canales.
Still image from the film Infinity ². Image Courtesy Ben Canales.

Infinity ² from Uncage the Soul Productions on Vimeo.

Israeli Shavit Rocket Delivers Malfunctioning Spy Satellite Into Orbit

Israel's Shavit 2 (Comet) rocket carried the Ofek-11 satellite into orbit on Sept. 13, 2016. Israeli media report that the satellite is malfunctioning. Image: Israeli Ministry of Defence.
Israel's Shavit 2 (Comet) rocket carried the Ofek-11 (Horizon) satellite into orbit on Sept. 13, 2016. Israeli media report that the satellite is malfunctioning. Image: Israeli Ministry of Defence.

Israel launched a Shavit2 rocket from its facility at Palmachim airbase on Sept. 13. The launch was the 10th one for the Shavit rocket system, which had its initial launch in 1988. The launch and delivery were successful, but Israeli media is reporting that the payload, the Ofek-11 satellite, is malfunctioning.

The Ofek-11 satellite in Tuesday’s launch is an optical imaging satellite, basically a spy satellite, operated by the Isreali Ministry of Defence. It operates at an altitude of 600 km. It’s orbital path is designed to pass over Israel’s region 6 times per day, allowing the Ministry of Defence to focus on targets of interest in their nation’s region.

Officials involved with the launch have successfully contacted the satellite. Amnon Harari, head of the Defence Ministry’s Space Department, told the Times of Israel that it was “not clear that everything was in order,” hours after the launch.

Doron Ofer is CEO of the Israel Aerospace Industries’ Space Division, the company that makes the Shavit rocket. He told the Times of Israel that due to the satellite’s path, and the rotation of the Earth, the satellite can only be contacted a few times per day. This complicates efforts to correct the satellite.

“We have downloaded some figures, and we are now checking them. It’s not functioning exactly the way we expected, and we don’t know what it’s status is,” Ofer said. “We are now working to stabilize it, but it will take some time because of the small amount of communication we have with it when it comes in our area.”

The Ofek-11 will be the 11th satellite that provides intelligence to the Israeli forces, but not much is known about its exact capabilities. For obvious reasons, the Israeli Defence Ministry is keeping things secret.

It is widely believed that this newest satellite is among the world’s most advanced satellite recon systems. It’s enhanced imaging system purportedly collects images at a ground resolution of 0.5 meters from its 600-Kilometer orbit.

The Ofek-11 surpasses its predecessor, Ofek-9, launched in 2010, which had only a 0.7 meter resolution. The Ofek-10 was a radar imaging satellite launched in 2014 to capture all-weather, day and night images at a resolution less than 1 meter. The overlapping nature of Israel’s satellite system eliminates any gaps in their ability to monitor their region.

Two weeks ago, Israel had another failure in its satellite efforts, though that one was much more catastrophic. The Amos-6 civilian communications satellite was going to be Israel’s largest satellite to date. However, the SpaceX rocket tasked with taking Amos-6 into orbit exploded on its Cape Canaveral launch pad.

Israel is the 8th country in the world to develop their own orbital launch capabilities. They launched their first satellite, the Ofek-1, aboard the maiden flight of their Shavit-1 rocket in 1988. Including that first launch, Israel has attempted 10 launches, and has been successful 8 times. All of those have been Ofek satellites, operated by the military.

All but one of Israel’s Ofek satellites have been launched by Israel’s Shavit-1 and Shavit-2 rockets. The lone exception is Ofek-8, also known as TecSar, launched aboard the Indian Polar Satellite Launch Vehicle (PSLV).

What is the Weather like on Jupiter?

Jupiter's Great Red Spot or GRS - taken by Hubble on April 21, 2014. Image Credit:

Welcome to a new series here at Universe Today! In this segment, we will be taking a look at the weather on other planets. First up, we take a look at the “King of Planets” – Jupiter!

One of the most obvious facts about the gas giant Jupiter is its immense size. With a mean radius of 69,911 ± 6 km (43441 mi) and a mass of 1.8986 × 1027 kg, Jupiter is almost 11 times the size of Earth, and just under 318 times Earth’s massive. But this “go big or go home” attitude extends far beyond the planet’s size.

When it comes to weather patterns, Jupiter is also an exercise in extremes. The planet experiences storms that can grow to thousands of kilometers in diameter in the space of a few hours. The planet also experiences windstorms, lightning, and auroras in some areas. In fact, the weather on Jupiter is so extreme that it can be seen from space!

Jupiter’s Atmosphere:

Jupiter is composed primarily of gaseous and liquid matter. It is the largest of the gas giants, and like them, is divided between a gaseous outer atmosphere and an interior that is made up of denser materials. It’s upper atmosphere is composed of about 88–92% hydrogen and 8–12% helium by percent volume of gas molecules, and approx. 75% hydrogen and 24% helium by mass, with the remaining one percent consisting of other elements.

This view compares a lucky imaging view of Jupiter from VISIR (left) at infrared wavelengths with a very sharp amateur image in visible light from about the same time (right). Credit: ESO/L.N. Fletcher/Damian Peach
This view compares a “lucky imaging” view of Jupiter from VISIR (left) at infrared wavelengths with a very sharp amateur image in visible light (right). Credit: ESO/L.N. Fletcher/Damian Peach

The atmosphere contains trace amounts of methane, water vapor, ammonia, and silicon-based compounds as well as trace amounts of benzene and other hydrocarbons. There are also traces of carbon, ethane, hydrogen sulfide, neon, oxygen, phosphine, and sulfur. Crystals of frozen ammonia have also been observed in the outermost layer of the atmosphere.

Jupiter is perpetually covered with clouds that are composed of these ammonia crystals, and possibly ammonium hydrosulfide. These clouds are located in the tropopause and are arranged into bands of different latitudes, known as “tropical regions”. The cloud layer is only about 50 km (31 mi) deep, and consists of at least two decks of clouds: a thick lower deck and a thin clearer region.

These clouds are also what gives the planet is banded appearance, with clouds of yellow, brown and white circling the surface rapidly. These bands are produced by air flowing in different directions at various latitudes. Lighter-hued areas where the atmosphere rises are called zones. Darker regions where air falls are called belts. When these opposing flows interact, storms and turbulence appear (aka. “zonal jets”).

The Great Red Spot:

As noted already, Jupiter experiences violent storms, which often take the form of zonal jets. In these weather fronts, wind speeds of 100 m/s (360 km/h) are common. But wind storms on the mighty planet can reach as high as 620 kph (385 mph). These storms can form within hours and become thousands of kilometers in diameter overnight.

The Juno spacecraft isn't the first one to visit Jupiter. Galileo went there in the mid 90's, and Voyager 1 snapped a nice picture of the clouds on its mission. Image: NASA
The Juno spacecraft isn’t the first one to visit Jupiter. Galileo went there in the mid 90’s, and Voyager 1 snapped a nice picture of the clouds on its mission. Image: NASA

One storm, the Great Red Spot, has been raging since at least the late 1600s – when Italian astronomer Giovanni Cassini made the first recorded observation of it. The storm has been shrinking and expanding throughout its history; but in 2012, it was suggested that the Giant Red Spot might eventually disappear.

This storm is one of the best known features in the Solar System. It is located 22° south of the equator and reaching sizes of up to 40,000 km across, it is larger in diameter than Earth. The storm rotates in a counter-clockwise motion, making it an anti-cyclonic storm.

It rotates differently than the rest of the atmosphere: sometimes faster and sometimes slower. During its recorded history it has traveled several times around the planet relative to any fixed position below it.

Meteorological Phenomena:

Jupiter also experience weather phenomena that are similar to those of Earth. These lightning storms, which have  been detected in Jupiter’s atmosphere. Scientists believe that these may be due to a thin layer of water clouds underlying the ammonia layer.

Composite images from the Chandra X-Ray Observatory and the Hubble Space Telescope show the hyper-energetic x-ray auroras at Jupiter. The image on the left is of the auroras when the coronal mass ejection reached Jupiter, the image on the right is when the auroras subsided. The auroras were triggered by a coronal mass ejection from the Sun that reached the planet in 2011. Image: X-ray: NASA/CXC/UCL/W.Dunn et al, Optical: NASA/STScI
Composite images from the Chandra X-Ray Observatory and the Hubble Space Telescope show the hyper-energetic x-ray auroras at Jupiter. Image: X-ray: NASA/CXC/UCL/W.Dunn et al, Optical: NASA/STScI

The presence of this water layer (and it’s polarity) would create the charge separation needed for lightning to occur. Observations of these electrical discharges indicate that they can be up to a thousand times as powerful as those observed here on the Earth.

Like Earth, Jupiter also experiences auroras near its northern and southern poles. But on Jupiter, the auroral activity is much more intense and rarely ever stops. The intense radiation, Jupiter’s powerful magnetic field, and the abundance of material from Io’s volcanoes that react with Jupiter’s ionosphere, create a light show that is truly spectacular.

What it comes down to is that Jupiter experiences weather that is similar to what we experience here on Earth. This includes wind storms, lightning, and auroras in both the northern and southern polar regions. The only difference is, in Jupiter’s case, the size and scale of the weather is much, much larger!

On Jupiter, as with everything else on the “King of Planets”, the weather is the result of titanic forces that produce some seriously powerful results. If any of these were to happen here on Earth, the results would be disasterous!

We have written many interesting articles about Jupiter here at Universe Today. Here’s Ten Interesting Facts About Jupiter, How Long Does it take to get to Jupiter?, How Much Bigger is Jupiter than Earth?, How Strong is Jupiter’s Gravity?, and Jupiter Compared to Earth.

For more information, check out NASA’s Solar System Exploration – Jupiter, and the facts about Jupiter from Space Facts.

Astronomy Cast also has episodes dedicated to Jupiter – Episode 56: Jupiter, and Episode 57: Jupiter’s Moons.

Sources:

Get That Geologist A Flight Suit!

Future missions to Mars and other locations in the Solar System may depend heavily on the skills of planetary geologists. Credit: NASA Ames Research Center

In the coming decades, the world’s largest space agencies all have some rather big plans. Between NASA, the European Space Agency (ESA), Roscosmos, the Indian Space Research Organisation (ISRO), or the China National Space Administration (CNSA), there are plans to return to the Moon, crewed missions to Mars, and crewed missions to Near-Earth Objects (NEOs).

In all cases, geological studies are going to be a major aspect of the mission. For this reason, the ESA recently unveiled a new training program known as the Pangaea course, a study program which focuses on identifying planetary geological features. This program showcases just how important planetary geologists will be to future missions.

Pangaea takes its name from the super-continent that that existed during the late Paleozoic and early Mesozoic eras (300 to 175 million years ago). Due to convection in Earth’s mantle, this continent eventually broke up, giving rise to the seven continents that we are familiar with today.

The super-continent Pangea during the Permian period (300 - 250 million years ago). Credit: NAU Geology/Ron Blakey
The super-continent Pangea during the Permian period (300 – 250 million years ago). Credit: NAU Geology/Ron Blakey

Francesco Sauro – a field geologist, explorer and the designer of the course – explained the purpose of Pangaea in an ESA press release:

“This Pangaea course – named after the ancient supercontinent – will help astronauts to find interesting rock samples as well as to assess the most likely places to find traces of life on other planets. We created a course that enables astronauts on future missions to other planetary bodies to spot the best areas for exploration and the most scientifically interesting rocks to take samples for further analysis by the scientists back on Earth.”

This first part of the course will take place this week, where astronaut trainer Matthias Maurer and astronauts Luca Parmitano and Pedro Duque will be learning from a panel of planetary geology experts. These lessons will include how to recognize certain types of rock, how to draw landscapes, and the exploration of a canyon that has sedimentary features similar to the ones observed in the Murray Buttes region, which was recently imaged by the Curiosity rover.

The geology panel will include such luminaries as Matteo Messironi (a geologist working on the Rosetta and ExoMars missions), Harald Hiesinger (an expert in lunar geology), Anna Maria Fioretti (a meteorite expert), and Nicolas Mangold (a Mars expert currently working with NASA’s Curiosity team).

Rock samples on display at ESA's Pangaea training for astronauts in identifying planetary geological features for future missions to the Moon, Mars and asteroids. Credit: ESA/L. Bessone
Rock samples on display at ESA’s Pangaea training course, which is intended to help astronauts in identify planetary geological features for future missions to the Moon, Mars and asteroids. Credit: ESA/L. Bessone

Once this phase of the course is complete, a series of field trips will follow to locations that were chosen because their geological features resemble those of other planets. This will include the town of Bressanone in northeastern Italy, which lies a few kilometers outside of the Brenner Pass (the part of the Alps that lies between Italy and Austria).

In many ways, the Pangaea course picks up where the Cooperative Adventure for Valuing and Exercising Human Behaviour and Performance Skills (CAVES) program left off. For several years now, the ESA has been conducting training missions in underground caverns in order to teach astronauts about working in challenging environments.

This past summer, the latest program involved a team of six international astronauts spending two weeks in a cave network in Sardinia, Italy. In this environment,  800-meters (2625 ft) beneath the surface, the team carried out a series of research and exploration activities designed to recreate aspects of a space expedition.

As the teams explore the caves of Sardinia, they encountered caverns, underground lakes and examples of strange microscopic life – all things they could encounter in extra-terrestrial environments. While doing this, they also get the change to test out new technologies and methods for research and experiments.

Sedimentary outcroppings in the Bressanoe region (left), compared to sedimentary deposits in the Murray Buttes region on Mars (right). Credit: ESA/I. Drozdovsky (left); NASA (right)
Sedimentary outcroppings in the Bressanoe region (left), compared to sedimentary deposits in the Murray Buttes region on Mars (right). Credit: ESA/I. Drozdovsky (left); NASA (right)

In a way that is similar to expeditions aboard the ISS, the program was designed to teach an international team of astronauts how to address the challenges of living and working in confined spaces. These include limited privacy, less equipment for hygiene and comfort, difficult conditions, variable temperatures and humidity, and extremely difficult emergency evacuation procedures.

Above all, the program attempts to foster teamwork, communication skills, decision-making, problem-solving, and leadership. This program is now an integral part of the ESA’s astronaut training and is conducted once a year. And as project leader Loredana Bessone explained, the Pangaea course fits with the aims of the CAVES program quite well.

“Pangaea complements our CAVES underground training,” she said. “CAVES focuses on team behaviour and operational aspects of a space mission, whereas Pangaea focuses on developing knowledge and skills for planetary geology and astrobiology.”

From all of these efforts, it is clear that the ESA, NASA and other space agencies want to make sure that future generations of astronauts are trained to conduct field geology and will be able to identify targets for scientific research. But of course, understanding the importance planetary geology in space exploration is not exactly a new phenomenon.

The six-member CAVES team in Sardinia, Italy, observing an underground pool. Credit: ESA/V.Crobu
The six-member CAVES team in Sardinia, Italy, observing an underground pool. Credit: ESA/V. Crobu

In fact, the study of planetary geology is rooted in the Apollo era, when it became a field separate from other fields of geological research. And geology experts played a very pivotal role when it came to selecting the landing sites of the Apollo missions. As Emily Lakdawalla, the Senior Editor of The Planetary Society (and a geologist herself), told Universe Today in a phone interview:

“The Apollo astronauts received training in field geology before they went to the Moon. Jim Head at Brown University, who was my advisor, was one person who provided that training. Before there were missions, the Lunar Orbiter program returned photos that geologists used to map the surface of the Moon and find good landing sites.”

This tradition is being carried on today with instruments like the Mars Global Surveyor. Before the Spirit and Opportunity rovers were deployed to the Martian surface, NASA scientists studied images taken by this orbiter to determine which potential landing sites would prove to be the valuable for conducting research.

And thanks to the experience gained by the Apollo missions and improvements made in both technology and instrumentation, the process has become much more sophisticated. Compared to the Apollo-era, today’s NASA mission planners have much more detailed information to go on.

Moon rocks from the Apollo 11 mission. Credit: NASA
Moon rocks from the Apollo 11 mission. Credit: NASA

“These days, the orbiter photos have such high resolutions that its just like having aerial photographs, which is something Earth geologists have always used as a tool to scope out an area before going to study it,” Lakdawalla said. “With these  photos, we can map out an area in detail before we send a rover, and determine where the most high-value samples will be.”

Looking ahead, everything that’s learned from sending astronauts to the Moon – and from the study of the lunar rocks they brought back – is going to play a vital role when it comes time to explore Mars, go back to the Moon, and investigate NEOs. As Lakdawalla explained, in each case, the purpose of the geological studies will be a bit different.

“The goal in obtaining samples from the Moon was about understanding the chronology of the Moon. The timescale we have developed for the Moon are anchored in the Apollo samples. But we think that the samples have been sampling one major impact – the Imbrium impact. The next Moon samples will attempt to sample other time periods so we can determine if our time scales are correct.”

“On Mars, the questions is, ‘what are the history of water on Mars’. You try to find rocks from orbit that will answer that questions – rocks that have either been altered by water or formed in water. And that is how you select your landing zone.”

And with future missions to NEOs, astronauts will be tasked with examining geological samples which date back to the formation of the Solar System. From this, we are likely to get a better understanding of how our Solar System formed and evolved over the many billion years it has existed.

Clearly, it is a good time to be a geologist, as their expertise will be called upon for future missions to space. Hope they like tang!

Further Reading: ESA, CSA

Hubble Images Three Debris Disks Around G-type Stars

An image of the circum-stellar disk around HD 207129. The three circled objects are background objects and part of the disk. Image: Hubble Space Telescope, Glenn Schneider et al 2016.
An image of the circum-stellar disk around HD 207129. The three circled objects are background objects and are not part of the disk. Image: Hubble Space Telescope, Glenn Schneider et al 2016.

A team using the Hubble Space Telescope has imaged circumstellar disk structures (CDSs) around three stars similar to our Sun. The stars are all G-type solar analogs, and the disks themselves share similarities with our Solar System’s own Kuiper Belt. Studying these CDSs will help us better understand their ring-like structure, and the formation of solar systems.

The team behind the study was led by Glenn Schneider of the Seward Observatory at the University of Arizona. They used the Hubble’s Space Telescope Imaging Spectrograph to capture the images. The stars in the study are HD 207917, HD 207129, and HD 202628.

Theoretical models of circumstellar disk dynamics suggest the presence of CDSs. Direct observation confirms their presence, though not many of these disks are within observational range. These new deep images of three solar analog CDSs are important. Studying the structure of these rings should lead to a better understanding of the formation of solar systems themselves.

A is the observed image of HD 207917. B is the best-fit debris ring model of the same star. Image: Hubble, G. Schneider et. al. 2016.
A is the observed image of HD 207917. B is the best-fit debris ring model of the same star. Image: Hubble, G. Schneider et. al. 2016.

Debris disks like these are separate from protoplanetary disks. Protoplanetary disks are a mixture of both gas and dust which exist around younger stars. They are the source material out of which planetesimals form. Those planetesimals then become planets.

Protoplanetary disks are much shorter-lived than CDSs. Whatever material is left over after planet formation is typically expelled from the host solar system by the star’s radiation pressure.

In circumstellar debris disks like the ones imaged in this study, the solar system is older, and the planets have already formed. CDSs like these have lasted this long by replenishing themselves. Collisions between larger bodies in the solar system create more debris. The resulting debris is continually ground down to smaller sizes by repeated collisions.

This process requires gravitational perturbation, either from planets in the system, or by binary stars. In fact, the presence of a CDSs is a strong hint that the solar system contains terrestrial planets.

A circumstellar disk of debris around a mature stellar system could indicate the presence of Earth-like planets. Credit: NASA/JPL
A circumstellar disk of debris around a mature stellar system could indicate the presence of Earth-like planets. Credit: NASA/JPL

The three disks in this study were viewed at intermediate inclinations. They scatter starlight, and are more easily observed than edge-on disks. Each of the three circumstellar disk structures possess “ring-like components that are more massive analogs of our solar system’s Edgeworth–Kuiper Belt,” according to the study.

The study authors expect that the images of these three disk structures will be studied in more detail, both by themselves and by others in future research. They also say that the James Webb Space Telescope will be a powerful tool for examining CDSs.

Read more: It’s Complicated: Hubble Survey Finds Unexpected Diversity in Dusty Discs Around Nearby Stars

What are the Parts of the Sun?

The interior structure of the Sun. Credit: Wikipedia Commons/kelvinsong

From here on Earth, the Sun like a smooth ball of light. And prior to Galileo’s discovery of sunposts, astronomers even thought it was a perfect orb with no imperfections. However, thanks to improved instruments and many centuries of study, we know that the Sun is much like the planets of our Solar System.

In addition to imperfections on its surface, the Sun is also made up of several layers, each of which serves its own purpose. It’s this structure of the Sun that powers this massive engine that provides the planets with all the light and heat they receive. And here on Earth, it is what provides all life forms with the energy they need to thrive and survive.

Composition:

If you could take the Sun apart, and stack up its various elements, you would find that the Sun is made of hydrogen (74%) and helium (about 24%). Astronomers consider anything heavier than helium to be a metal. The remaining amount of the Sun is made of iron, nickel, oxygen, silicon, sulfur, magnesium, carbon, neon, calcium and chromium. In fact, the Sun is 1% oxygen; and everything else comes out of that last 1%.

Where did these elements come from? The hydrogen and helium came from the Big Bang. In the early moments of the Universe, the first element, hydrogen, formed from the soup of elementary particles. The pressure and temperatures were still so intense that the entire Universe had the same conditions as the core of a star.

Hydrogen was fused into helium until the Universe cooled down enough that this reaction couldn’t happen any more. The ratios of hydrogen and helium that we see in the Universe today were created in those first few moments after the Big Bang. The other elements were created in other stars. Stars are constantly fusing hydrogen into helium in their cores.

Once the hydrogen in the core runs out, they switch to fusing heavier and heavier elements, like helium, lithium, oxygen. Most of the heavier metals we see in the Sun were formed in other stars at the end of their lives. The heaviest elements, like gold and uranium, were formed when stars many times more massive that our Sun detonated in supernova explosions.

In a fraction of a second, as a black hole was forming, elements were crushed together in the intense heat and pressure to form the heaviest elements. The explosion scattered these elements across the region, where they could contribute to the formation of new stars.

Our Sun is made up of elements left over from the Big Bang, elements formed from dying stars, and elements created in supernovae. That’s pretty amazing.

Structure:

Although the Sun is mostly just a ball of hydrogen and helium, it’s actually broken up into distinct layers. The layers of the Sun are created because the temperatures and pressures increase as you move towards the center of the Sun. The hydrogen and helium behave differently under the changing conditions.

The Core: Let’s start at the innermost layer of the Sun, the core of the Sun. This is the very center of the Sun, where temperatures and pressures are so high that fusion can happen. The Sun is combining hydrogen into helium atoms, and this reaction gives off the light and heat that we see here on Earth. The density of the core is 150 times the density of water, and the temperatures are thought to be 13,600,000 degrees Kelvin.

Astronomers believe that the core of the Sun extends from the center out to about 0.2 solar radius. And within this region, temperatures and pressures are so high that hydrogen atoms are torn apart to form separate protons, neutrons and electrons. With all of these free floating particles, the Sun is able to reform them into atoms of helium.

This reaction is exothermic. That means that the reaction gives off a tremendous amount of heat – 3.89 x 1033 ergs of energy every second. The light pressure of all this energy streaming from the core of the Sun is what stops it from collapsing inward on itself.

Radiative Zone: The radiative zone of the Sun starts at the edge of the core of the Sun (0.2 solar radii), and extends up to about 0.7 radii. Within the radiative zone, the solar material is hot and dense enough that thermal radiation transfers the heat of the core outward through the Sun.

The core of the Sun is where nuclear fusion reactions are happening – protons are merged together to create atoms of helium. This reaction produces a tremendous amount of gamma radiation. These photons of energy are emitted, absorbed, and then emitted again by various particles in the radiative zone.

The path that photons take is called the “random walk”. Instead of going in a straight beam of light, they travel in a zigzag direction, eventually reaching the surface of the Sun. In fact, it can take a single photon upwards of 200,000 years to make the journey through the radiative zone of the Sun.

As they transfer from particle to particle, the photons lose energy. That’s a good thing, since we wouldn’t want only gamma radiation streaming from the Sun. Once these photons reach space, they take a mere 8 minutes to get to Earth.

Most stars will have radiative zones, but their size depends on the star’s size. Small stars will have much smaller radiative zones, and the convective zone will take up a larger portion of the star’s interior. The smallest stars might not have a radiative zone at all, with the convective zone reaching all the way down to the core. The largest stars would have the opposite situation, where the radiative zone reaches all the way up to the surface.

Convective Zone: Outside the radiative zone is another layer, called the convective zone, where heat from inside the Sun is carried up by columns of hot gas. Most stars have a convective zone. In the case of the Sun, it starts at around 70% of the Sun’s radius and goes to the outer surface (the photosphere).

Gas deeper inside the star is heated up so that it rises, like globs of wax in a lava lamp. As it gets to the surface, the gas loses some of its heat, cools down, and sinks back towards the center to pick up more heat. Another example would be a pot of boiling water on the stove.

The surface of the Sun looks granulated. These granules are the columns of hot gas that carry heat to the surface. They can be more than 1,000 km across, and typically last about 8 to 20 minutes before dissipating. Astronomers think that low mass stars, like red dwarfs, have a convective zone that goes all the way down to the core. Unlike the Sun, they don’t have a radiative zone at all.

Photosphere: The layer of the Sun that we can see from Earth is called the photosphere. Below the photosphere, the Sun becomes opaque to visible light, and astronomers have to use other methods to probe its interior. The temperature of the photosphere is about 6,000 Kelvin, and gives off the yellow-white light that we see.

Above the photosphere is the atmosphere of the Sun. Perhaps the most dramatic of these is the corona, which is visible during a total solar eclipse.

This graphic shows a model of the layers of the Sun, with approximate mileage ranges for each layer: for the inner layers, the mileage is from the sun's core; for the outer layers, the mileage is from the sun's surface. The inner layers are the Core, Radiative Zone and Convection Zone. The outer layers are the Photosphere, the Chromosphere, the Transition Region and the Corona. Credit: NASA
Graphic showing a model of the layers of the Sun, with approximate mileage ranges for each layer. Credit: NASA

Diagram:

Below is a diagram of the Sun, originally developed by NASA for educational purposes.

  • Visible, IR and UV radiation – The light that we see coming from the Sun is visible, but if you close your eyes and just feel the warmth, that’s IR, or infrared radiation. And the light that gives you a sunburn is ultraviolet (UV) radiation. The Sun produces all of these wavelengths at the same time.
  • Photosphere 6000 K – The photosphere is the surface of the Sun. This is the region where light from the interior finally reaches space. The temperature is 6000 K, which is the same as 5,700 degrees C.
  • Photosphere 6000 K – The photosphere is the surface of the Sun. This is the region where light from the interior finally reaches space. The temperature is 6000 K, which is the same as 5,700 degrees C.
  • Radio emissions – In addition to visible, IR and UV, the Sun also gives off radio emissions, which can be detected by a radio telescope. These emissions rise and fall depending on the number of sunspots on the surface of the Sun.
  • Coronal Hole – These are regions on the Sun where the corona is cooler, darker and has less dense plasma.
  • 2100000 – This is the temperature of the Sun’s radiative zone.
  • Convective zone/Turbulent convection – This is the region of the Sun where heat from the core is transferred through convection. Warm columns of plasma rise to the surface in columns, release their heat and then fall back down to heat up again.
  • Coronal loops – These are loops of plasma in the Sun’s atmosphere that follows magnetic flux lines. They look like big arches, stretching up from the surface of the Sun for hundreds of thousands of kilometers.
  • Core – The is the heart of the Sun, where the temperatures and pressures are so high that nuclear fusion reactions can happen. All of the energy coming from the Sun originates from the core.
  • 14500000 K – The temperature of the core of the Sun.
  • Radiative Zone – The region of the Sun where energy can only be transferred through radiation. It can take a single photon 200,000 years to get from the core, through the radiative zone, out to the surface and into space.
  • Neutrinos – Neutrinos are nearly mass-less particles blasted out from the Sun as part of the fusion reactions. There are millions of neutrinos passing through your body every second, but they don’t interact, so you can’t feel them.
  • Chromospheric Flare – The Sun’s magnetic field can get twisted up and then snap into a different configuration. When this happens, there can be powerful X-ray flares emanating from the surface of the Sun.
  • Magnetic Field Loop – The Sun’s magnetic field extends out above its surface, and can be seen because hot plasma in the atmosphere follows the field lines.
  • Spot – A sunspot. These are areas on the Sun’s surface where the magnetic field lines pierce the surface of the Sun, and they’re relatively cooler than the surrounding areas.
  • Prominence – A bright feature that extends above the surface of the Sun, often in the shape of a loop.
  • Energetic particles – There can be energetic particles blasting off the surface of the Sun to create the solar wind. In solar storms, energetic protons can be accelerated to nearly the speed of light.
  • X-rays – In addition to the wavelengths we can see, there are invisible X-rays coming from the Sun, especially during flares. The Earth’s atmosphere protects us from this radiation.
  • Bright spots and short-lived magnetic regions – The surface of the Sun has many brighter and dimmer spots caused by changing temperature. The temperature changes from the constantly shifting magnetic field.

Yes, the Sun is like an onion. Peel back one layer and you’ll find many more. But in this case, each layers is responsible for a different function. And what they add to is a giant furnace and light source that keeps us living beings here on Earth warm and illuminated!

And be sure to enjoy this video from the NASA Goddard Center, titled “Snapshots from the Edge of the Sun”:

We have written many interesting articles about the Sun here at Universe Today. Here’s Ten Interesting Facts About the Sun, What Color is the Sun?, What is the Life Cycle of the Sun?, What Kind of Star is the Sun?, How Far is the Earth from the Sun?, and Could We Terraform the Sun?

For more information, check out NASA’s page on the Sun, and Sun Facts at Eight Planets.

Astronomy Cast also has an episode on the subject: Episode 320: The Layers of the Sun

Sources:

Bound for Bennu, OSIRIS-REx Begins Trailblazing Asteroid Sampling Sortie for Life’s Origins – Sunset Launch Gallery

United Launch Alliance Atlas V rocket lifts off from Space Launch Complex 41 at Cape Canaveral Air Force Station carrying NASA’s Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer, or OSIRIS-REx spacecraft on the first U.S. mission to sample an asteroid, retrieve at least two ounces of surface material and return it to Earth for study. Liftoff was at 7:05 p.m. EDT on September 8, 2016 in this remote camera view taken from inside the launch pad perimeter. Note the newly install crew access arm and white room for astronaut flights atop Atlas starting in early 2018. Credit: Ken Kremer/kenkremer.com
United Launch Alliance Atlas V rocket lifts off from Space Launch Complex 41 at Cape Canaveral Air Force Station carrying NASA’s Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer, or OSIRIS-REx spacecraft on the first U.S. mission to sample an asteroid, retrieve at least two ounces of surface material and return it to Earth for study.  Liftoff was at 7:05 p.m. EDT on September 8, 2016 in this remote camera view taken from inside the launch pad perimeter.  Note the newly install crew access arm and white room for astronaut flights atop Atlas starting in early 2018.   Credit: Ken Kremer/kenkremer.com
United Launch Alliance Atlas V rocket lifts off from Space Launch Complex 41 at Cape Canaveral Air Force Station carrying NASA’s Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer, or OSIRIS-REx spacecraft on the first U.S. mission to sample an asteroid, retrieve at least two ounces of surface material and return it to Earth for study. Liftoff was at 7:05 p.m. EDT on September 8, 2016 in this remote camera view taken from inside the launch pad perimeter. Note the newly installed crew access arm and white room for astronaut flights atop Atlas starting in early 2018. Credit: Ken Kremer/kenkremer.com

KENNEDY SPACE CENTER, FL – Bound for Bennu, NASA’s OSIRIS-REx robotic explorer began a trailblazing 7 year round trip sampling sortie on Sept. 8 in search of the origin of life with a spectacular sky show – thrilling spectators ringing the Florida Space Coast.

Hordes of space enthusiasts from all across the globe descended on the Kennedy Space Center and Cape Canaveral region for the chance of a lifetime to witness a once in a lifetime liftoff to the carbon rich asteroid – which could potentially bring back samples infused with the organic chemicals like amino acids that are the building blocks of life as we know it.

NASA’s Origins, Spectral Interpretation, Resource Identification, Security – Regolith Explorer (OSIRIS-REx) spacecraft departed Earth with an on time engine ignition of a United Launch Alliance Atlas V rocket under crystal clear skies on Thursday, September 8 at 7:05 p.m. EDT from Space Launch Complex 41 at Cape Canaveral Air Force Station.

Blastoff of NASA’s OSIRIS-Rex asteroid sampling spacecraft on September 8, 2016 from Cape Canaveral Air Force Station, FL as seen from Playalinda Beach.  Credit: Jillian Laudick
Blastoff of NASA’s OSIRIS-Rex asteroid sampling spacecraft on September 8, 2016 from Cape Canaveral Air Force Station, FL as seen from Playalinda Beach. Credit: Jillian Laudick

Everything went exactly according to plan for the daring mission bolding seeking to gather rocks and soil from Bennu – using an ingenious robotic arm named TAGSAM – and bring at least a 60-gram (2.1-ounce) sample back to Earth in 2023 for study by scientists using the world’s most advanced research instruments.

“We got everything just exactly perfect,” said Dante Lauretta, the principal investigator for OSIRIS-REx at the University of Arizona, at the post launch briefing at the Kennedy Space Center. “We hit all our milestone within seconds of predicts.

The space rock measures about the size of a small mountain at about a third of a mile in diameter.

And the picture perfect near sunset launch rewarded photographers from near and far with a spectacular series of richly hued photo and video recordings.

So I’ve gathered here a variety of launch imagery from multiple vantage points shot by friends, colleagues and myself – for the enjoyment of readers of Universe Today and Beyond!

Liftoff of NASA’s OSIRIS-Rex asteroid sampling spacecraft on September 8, 2016 from Cape Canaveral Air Force Station, FL.  Credit: Julian Leek
Liftoff of NASA’s OSIRIS-Rex asteroid sampling spacecraft on September 8, 2016 from Cape Canaveral Air Force Station, FL. Credit: Julian Leek

As you’ll see and hear the ULA Atlas V rocket integrated with OSIRIS-Rex on top thundered off the Cape’s pad 41 and shot skyward straight up along an equatorial path into Florida’s sun.

From every vantage point the rocket and its ever expanding vapor trail were visible for some 4 or 5 minutes or more. From my location on the roof of NASA’s Vehicle Assembly Building (VAB) the rocket finally arched over nearly straight above us and the sun produced a magnificent thin and nearly straight shadow of the vapor trail on the ground running out to the Atlantic Ocean towards Africa.

Blastoff of NASA’s OSIRIS-Rex asteroid sampling spacecraft on September 8, 2016 from Cape Canaveral Air Force Station, FL as seen from Playalinda Beach.  Credit: John Kraus
Blastoff of NASA’s OSIRIS-Rex asteroid sampling spacecraft on September 8, 2016 from Cape Canaveral Air Force Station, FL as seen from Playalinda Beach. Credit: John Kraus

It was truly an unforgettable sight to behold. And folks at Playalinda Beach, the best public viewing spot just a few miles north of pad 40 had an uninhibited view of the rocket to the base of the pad – while they waded and swam in the oceans waters with waves crashing on shore as the Atlas rocket blasted to space.

OSIRIS-REx separated as planned from the Atlas V rockets liquid oxygen and liquid hydrogen fueled second stage rocket to fly free at 8:04 p.m. on Sept. 8 – 55 minutes after launch.

The pair of solar arrays deployed as planned to provide the probes life giving power.

The spacecraft was built by prime contractor Lockheed.

“The spacecraft is healthy and functioning properly,” Richard Kuhns, Lockheed Martin OSIRIS-REx program manager, told me in an interview at the post-launch briefing.

Members of the OSIRIS-REx mission team celebrate the successful spacecraft launch on Sept. 8, 2016 atop ULA Atlas V at the post-launch briefing at the Kennedy Space Center, FL. Principal Investigator Dante Lauretta is 4th from right,  NASA Planetary Science Director Jim Green is center, 5th from left. Credit: Ken Kremer/kenkremer.com
Members of the OSIRIS-REx mission team celebrate the successful spacecraft launch on Sept. 8, 2016 atop ULA Atlas V at the post-launch briefing at the Kennedy Space Center, FL. Principal Investigator Dante Lauretta is 4th from right, NASA Planetary Science Director Jim Green is center, 5th from left. Richard Kuhns, Lockheed Martin OSIRIS-REx program manager, 2nd from right. Credit: Ken Kremer/kenkremer.com

“The primary objective of the OSIRIS-Rex mission is to bring back pristine material from the surface of the carbonaceous asteroid Bennu, OSIRIS-Rex Principal Investigator Dante Lauretta told Universe Today in a prelaunch interview in the KSC cleanroom with the spacecraft as the probe was undergoing final preparations for shipment to the launch pad.

“We are interested in that material because it is a time capsule from the earliest stages of solar system formation.”

“It records the very first material that formed from the earliest stages of solar system formation. And we are really interested in the evolution of carbon during that phase. Particularly the key prebiotic molecules like amino acids, nucleic acids, phosphates and sugars that build up. These are basically the biomolecules for all of life.”

The asteroid is 1,614-foot (500 m) in diameter and crosses Earth’s orbit around the sun every six years.

After a two year flight through space, including an Earth swing by for a gravity assisted speed boost in 2017, OSIRIS-REx will reach Bennu in Fall 2018 to begin about 2 years of study in orbit to determine the physical and chemical properties of the asteroid in extremely high resolution.

While orbiting Bennu starting in 2018 it will move in close to explore the asteroid for about two years with its suite of science instruments, scanning in visible and infrared light. After a thorough site selection, it will move carefully towards the surface and extend the 11 foot long TAGSAM robotic arm and snatch pristine soil samples containing organic materials from the surface using the TAGSAM collection dish over just 3 to 5 seconds.

Once a good sample collection is confirmed, the dish will then be placed inside the Earth return canister and be brought back to Earth for study by researchers using all of the most sophisticated science instruments available to humankind.

Using the 11 foot long TAGSAM robotic arm that functions somewhat like a pogo stick, OSIRIS-REx will gather rocks and soil and bring at least a 60-gram (2.1-ounce) sample back to Earth on Sept 24, 2023. It has the capacity to scoop up to about 2 kg or more.

ULA Atlas V rocket lifts off from Space Launch Complex 41 at Cape Canaveral Air Force Station carrying NASA’s OSIRIS-REx asteroid sampling spacecraft on September 8, 2016 from Cape Canaveral Air Force Station, FL, in this remote camera view taken from inside the launch pad perimeter.  Credit: Ken Kremer/kenkremer.com
ULA Atlas V rocket lifts off on September 8, 2016 from Space Launch Complex 41 at Cape Canaveral Air Force Station carrying NASA’s OSIRIS-REx asteroid sampling spacecraft, in this remote camera view taken from inside the launch pad perimeter. Credit: Ken Kremer/kenkremer.com

The two stage ULA Atlas V performed flawlessly and delivered OSIRIS-Rex into a hyperbolic trajectory away from Earth.

The 189 foot tall ULA Atlas V rocket launched in the rare 411 configuration for only the 3rd time on this mission – which is the 65th for the Atlas V.

The Atlas 411 vehicle includes a 4-meter diameter large Payload Fairing (PLF) and one solid rocket booster that augments the first stage. The Atlas booster for this mission is powered by the RD AMROSS RD-180 engine and the Centaur upper stage was powered by the Aerojet Rocketdyne RL10A.

The RD-180 burns RP-1 (Rocket Propellant-1 or highly purified kerosene) and liquid oxygen and delivers 860,200 lb of thrust at sea level.

The strap on solid delivers approximately 348,500 pounds of thrust.

The Centaur delivers 22, 230 lbf of thrust and burns liquid oxygen and liquid hydrogen.

The solid was jettisoned at 139 seconds after liftoff.

Launch of NASA’s OSIRIS-REx on September 8, 2016 from Cape Canaveral Air Force Station, FL as seen from LC-39 Gantry.  Credit: Jen Saxby
Launch of NASA’s OSIRIS-REx on September 8, 2016 from Cape Canaveral Air Force Station, FL as seen from LC-39 Gantry. Credit: Jen Saxby

This is ULA’s eighth launch in 2016 and the 111th successful launch since the company was formed in December 2006.

NASA’s OSIRIS-REx blasts off to asteroid Bennu on ULA Atlas V rocket prior on Sept. 8, 2016 from Space Launch Complex 41 on Cape Canaveral Air Force Station, FL, as seen from the VAB roof.  Credit: Lane Hermann/SpaceHeadNews
NASA’s OSIRIS-REx blasts off to asteroid Bennu on ULA Atlas V rocket prior on Sept. 8, 2016 from Space Launch Complex 41 on Cape Canaveral Air Force Station, FL, as seen from the VAB roof. Credit: Lane Hermann/SpaceHeadNews

OSIRIS-REx will return the largest sample from space since the American and Soviet Union’s moon landing missions of the 1970s.

Watch these pair of up close videos (from myself and Jeff Seibert) captured directly at the pad with the sights and sounds of the fury of launch:

Video Caption: ULA Atlas V rocket lifts off on September 8, 2016 from Space Launch Complex 41 at Cape Canaveral Air Force Station carrying NASA’s OSIRIS-REx asteroid sampling spacecraft, in this remote camera view taken from inside the launch pad perimeter. Credit: Ken Kremer/kenkremer.com

Video Caption: Compilation of my launch videos from the ULA Atlas 5 launch in support of the NASA OSIRIS_REx asteroid sample return mission to the asteroid Bennu (#101955). It was launched on September 8th, 2016 from Pad 41 of CCAFS. It is scheduled to land in UTAH with asteroid samples on September 24, 2023. Credit: Jeff Seibert

OSIRIS-REx is the third mission in NASA’s New Frontiers Program, following New Horizons to Pluto and Juno to Jupiter, which also launched on Atlas V rockets.

NASA’s Goddard Space Flight Center in Greenbelt, Maryland, is responsible for overall mission management.

OSIRIS-REx complements NASA’s Asteroid Initiative – including the Asteroid Redirect Mission (ARM) which is a robotic spacecraft mission aimed at capturing a surface boulder from a different near-Earth asteroid and moving it into a stable lunar orbit for eventual up close sample collection by astronauts launched in NASA’s new Orion spacecraft. Orion will launch atop NASA’s new SLS heavy lift booster concurrently under development.

Launch of NASA’s OSIRIS-REx on September 8, 2016 from Cape Canaveral Air Force Station, FL as seen from VAB roof.  Credit:  J.Sekora/SEKORAPHOTO
Launch of NASA’s OSIRIS-REx on September 8, 2016 from Cape Canaveral Air Force Station, FL as seen from VAB roof. Credit: J.Sekora/SEKORAPHOTO

Watch for Ken’s continuing OSIRIS-REx mission and launch reporting from on site at the Kennedy Space Center and Cape Canaveral Air Force Station, FL.

Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.

Ken Kremer

NASA’s OSIRIS-Rex asteroid sampling spacecraft streaks to orbit on September 8, 2016 from Cape Canaveral Air Force Station, FL as seen from Playalinda Beach.  Credit: Jillian Laudick
NASA’s OSIRIS-Rex asteroid sampling spacecraft streaks to orbit on September 8, 2016 from Cape Canaveral Air Force Station, FL as seen from Playalinda Beach. Credit: Jillian Laudick
Liftoff of NASA’s Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer, or OSIRIS-Rex asteroid sampling spacecraft on September 8, 2016 from Cape Canaveral Air Force Station, FL.  Credit: Ken Kremer/kenkremer.com
Liftoff of NASA’s Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer, or OSIRIS-Rex asteroid sampling spacecraft on September 8, 2016 from Cape Canaveral Air Force Station, FL. Credit: Ken Kremer/kenkremer.com
A United Launch Alliance Atlas V rocket lifts off from Space Launch Complex 41 at Cape Canaveral Air Force Station carrying NASA’s Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer, or OSIRIS-REx spacecraft on the first U.S. mission to sample an asteroid, retrieve at least two ounces of surface material and return it to Earth for study.  Liftoff was at 7:05 p.m. EDT on September 8, 2016.  Credit: Ken Kremer/kenkremer.com
A United Launch Alliance Atlas V rocket lifts off from Space Launch Complex 41 at Cape Canaveral Air Force Station carrying NASA’s Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer, or OSIRIS-REx spacecraft on the first U.S. mission to sample an asteroid, retrieve at least two ounces of surface material and return it to Earth for study. Liftoff was at 7:05 p.m. EDT on September 8, 2016. Credit: Ken Kremer/kenkremer.com
View of science instrument suite and TAGSAM robotic sample return arm on NASA’s OSIRIS-REx asteroid sampling spacecraft inside the Payloads Hazardous Servicing Facility at NASA's Kennedy Space Center.  Probe is slated for Sep. 8, 2016 launch to asteroid Bennu from Cape Canaveral Air Force Station, FL.  Credit: Ken Kremer/kenkremer.com
View of science instrument suite and TAGSAM robotic sample return arm on NASA’s OSIRIS-REx asteroid sampling spacecraft inside the Payloads Hazardous Servicing Facility at NASA’s Kennedy Space Center. Probe is slated for Sep. 8, 2016 launch to asteroid Bennu from Cape Canaveral Air Force Station, FL. Credit: Ken Kremer/kenkremer.com

Messier 23 – The NGC 6494 Open Star Cluster

Messier 23, Messier 21, Trifid Nebula (M20) and Omega Nebula (M17). Credit: Wikisky

Welcome back to Messier Monday! In our ongoing tribute to the great Tammy Plotner, we take a look at the Messier 23 open star cluster. Enjoy!

Back in the 18th century, famed French astronomer Charles Messier noted the presence of several “nebulous objects” in the night sky. Having originally mistaken them for comets, he began compiling a list of these objects so that other astronomers wouldn’t make the same mistake. Consisting of 100 objects, the Messier Catalog has come to be viewed as a major milestone in the study of Deep Space Objects.

One of these objects is Messier 23 (aka. NGC 6494), a large open star cluster that is located in the constellation Sagittarius. Given its luminosity, it can be found quite easily in the rich star fields of the summer Milky Way using small telescopes and even binoculars.

Description:

Located some 2,150 light years (659 Parsecs) away from Earth, this vast cloud of 176 confirmed stars stretches across 15 to 20 light years of space. At an estimated 220 to 300 million years old, Messier 23 is on the “senior citizen” list of galactic open clusters in our galaxy. At this age, its hottest stars reach spectral type B9, and it even contains a few blue straggler candidates.

Messier 23. Atlas Image mosaic obtained as part of the Two Micron All Sky Survey (2MASS), a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technology, funded by the National Aeronautics and Space Administration and the National Science Foundation.
Mosaic image obtained as part of the Two Micron All Sky Survey (2MASS). Credit: UofM/IPAC/Caltech/NASA/NSF

Given that M23 has spent many centuries sweeping through the interstellar medium, astronomers have wondered how this would affect its metal content. Using UBV photometry, astronauts examined the metallicity of M23, and determined that it had no discernible effect. As W.L. Sanders wrote of the cluster in 1990:

“UBV photometric observations of 176 stars in the galactic cluster NGC 6494 are presented and analyzed. The effect of a gas poor environment on the metal abundance of NGC 6494 is studied. It is determined that the metallicity of NGC 6494, which has a delta(U – B) value = + 0.02, is not affected by the interarm region in which it dwelled.”

At the same time, astronomers have discovered that some of M23’s older stars – the red giants – are suffering mass loss. As G. Barbaro (et al.) of the Istituto di Fisica dell’Universita put it in 1969:

“A statistical research on evolved stars beyond hydrogen exhaustion is performed by comparing the H-R diagrams of about 60 open clusters with a set of isochronous curves without mass loss derived from Iben’s evolutionary tracks and time scales for Population I stars. Interpreting the difference in magnitude between the theoretical positions thus calculated and the observed ones as due to mass loss, when negative, the results indicate that this loss may be conspicuous only for very massive and red stars. However, a comparison with an analogous work of Lindoff reveals that the uncertainties connected with the bolometric and color corrections may invalidate by a large amount the conclusions which might be drawn from such research.”

Close-up image of the core of M23, showing some of its brightest member stars. Credit: Sharp/NOAO/AURA/NSF
Close-up of the core of M23, showing some of its brightest member stars. Credit: Sharp/NOAO/AURA/NSF

However, the most recent studies show that we have to determine radial velocities before we can really associate red giants as being cluster members. J.C. Mermilliod of Laboratoire d’Astrophysique de l’Ecole wrote in his 2008 study, “Red giants in open clusters“:

“The present material, combined with recent absolute proper motions, will permit various investigation of the galactic distribution and space motions of a large sample of open clusters. However, the distance estimates still remain the weakest part of the necessary data. This paper is the last one in this series devoted to the study of red giants in open clusters based on radial velocities obtained with the CORAVEL instruments.”

History of Observation:

This neat and tidy galactic star cluster was one of the original discoveries of Charles Messier. As he recorded of the cluster when first viewing it, which occurred on June 20th, 1764:

“In the night of June 20 to 21, 1764, I determined the position of a cluster of small stars which is situated between the northern extremity of the bow of Sagittarius and the right foot of Ophiuchus, very close to the star of sixth magnitude, the sixty-fifth of the latter constellation [Oph], after the catalog of Flamsteed: These stars are very close to each other; there is none which one can see easily with an ordinary refractor of 3 feet and a half, and which was taken for these small stars. The diameter of all is about 15 minutes of arc. I have determined its position by comparing the middle with the star Mu Sagittarii: I have found its right ascension of 265d 42′ 50″, and its declination of 18d 45′ 55″, south.”

The M23 open star cluster, as it appears in the night sky, flanked by M8 (Lagoon), M16 (Eagle), M17 (Omega), M20 (Trifid) and other deep sky objects. Credit & Copyright: Fernando Cabrerizo/NASA
The M23 open star cluster, as it appears in the night sky (a patch of red), flanked by M8 (Lagoon), M16 (Eagle), M17 (Omega), M20 (Trifid) and other deep sky objects. Credit & Copyright: Fernando Cabrerizo/NASA

While William Herschel did not publish his observations of Messier’s objects, he was still an avid observer. So of course, he had to look at this cluster, and wrote the following observations in his personal notes:

“A cluster of beautiful scattered, large stars, nearly of equal magnitudes (visible in my finder), it extends much farther than the field of the telescope will take in, and in the finder seems to be a nebula of a lengthened form extending to about half a degree.”

In July of 1835, Admiral Smyth would make an observation of Messier 23 and once again add his colorful remarks to the timeline:

“A loose cluster in the space between Ophiuchus’s left leg and the bow of Sagittarius. This is an elegant sprinkling of telescopic stars over the whole field, under a moderate magnifying power; the most clustering portion is oblique, in the direction sp to nf [south preceding to north following, SW to NE], with a 7th-magnitude star in the latter portion. The place registered it that of a neat pair, of the 9th and 10th magnitudes, of a lilac hue, and about 12″ apart. This object was discovered by Messier 1764, and it precedes a rich out-cropping of the Milky Way. The place is gained by differentiating the cluster with Mu Sagittarii, from which it bears north-west, distant about 5 deg, the spot being directed to by a line from Sigma on the shoulder, through Mu at the tip of the bow.”

Remember when observing Messier 23 that it won’t slap you in the face like many objects. Basically, it looks like a stellar scattering of freckles across the face of the sky when fully-resolved. It’s actually one of those objects that’s better to view with binoculars and low power telescopes.

messier-23-location

Locating Messier 23:

M23 can be easily found with binoculars about a finger’s width north and two finger widths west of Mu Sagittarii. Or, simply draw a mental line between the top star in the teapot lid (Lambda) and Xi Serpentis. You’ll find a slight compression in the star field about halfway between these two stars that shows up as an open cluster with binoculars.

Using a finderscope, the object will appear nicely as a hazy spot. And for those using telescopes of any size, you’ll need to use fairly low magnification to help set this cluster apart from the surrounding star field, and it will resolve well to almost all instruments.

And here are the quick facts on this object to help you get started:

Object Name: Messier 23
Alternative Designations: M23, NGC 6494
Object Type: Open Star Cluster
Constellation: Sagittarius
Right Ascension: 17 : 56.8 (h:m)
Declination: -19 : 01 (deg:m)
Distance: 2.15 (kly)
Visual Brightness: 6.9 (mag)
Apparent Dimension: 27.0 (arc min)

We have written many interesting articles about Messier Objects here at Universe Today. Here’s Tammy Plotner’s Introduction to the Messier Objects, , M1 – The Crab Nebula, M8 – The Lagoon Nebula, and David Dickison’s articles on the 2013 and 2014 Messier Marathons.

Be to sure to check out our complete Messier Catalog. And for more information, check out the SEDS Messier Database.

Sources:

Blue Origin Goes Big With New Glenn Rocket

Size comparison between the New Glenn and all other rockets currently in operations (with the Saturn V for comparison). Credit: Blue Origin

Space exploration is becoming a lucrative domain for private aerospace companies (aka. the NewSpace industry). With opportunities for launch and resupply services growing, costs dwindling, and the cancellation of the Space Shuttle Program, private companies have been stepping up in recent years to provide their own launch vehicles and services to fill the gap.

Take Jeff Bezos, for example. Back in 2000, the founder of Amazon.com created Blue Origin to fulfill his lifelong dream of colonizing space. For years, Bezos and the company he founded have been working to produce their own fleet of reusable rockets. And as of the morning of Monday, Sept. 12th, he unveiled their newest and heaviest rocket – the New Glenn.

Much like SpaceX, Blue Origin has been committed to the creation of reusable rocket technology. This was made clear with the development of the New Shepard suborbital rocket, which was unveiled in 2006. Named in honor of the first American astronaut to go into space (Alan Shepard), this rocket made its first flight in April of 2015 and has had an impressive record, nailing four out of five soft landings in the space of just over a year.

New Shepard comes in for a landing with drag brakes and landing gear deployed. Image: Blue Origin.
New Shepard comes in for a landing with drag brakes and landing gear deployed. Credit: Blue Origin.

With the New Glenn – named in honor of astronaut John Glenn, the first American astronaut to orbit the Earth – the company now intends to take the next step, offering launch services beyond Low-Earth Orbit (LEO) and for crewed missions. As Bezos said during the press conference:

“New Glenn is designed to launch commercial satellites and to fly humans into space. The three-stage variant-with its high specific impulse hydrogen upper stage—is capable of flying demanding beyond-LEO missions.”

According to Bezos, Blue Origin will have both a two-stage and three-stage variant of the rocket. Whereas the two-stage will provide heavier lift capacity to LEO, the three-stage will be able to reach further, and will the company’s go-to when sending crewed missions into space. Work on the rocket began back in 2012, and the company hopes to make their first launch prior to 2020.

As Bezos said during the unveiling, this rocket carries on in the same tradition that inspired the creation of the New Shepard:

“Building, flying, landing, and re-flying New Shepard has taught us so much about how to design for practical, operable reusability. And New Glenn incorporates all of those learnings. Named in honor of John Glenn, the first American to orbit Earth, New Glenn is 23 feet in diameter and lifts off with 3.85 million pounds of thrust from seven BE-4 engines. Burning liquefied natural gas and liquid oxygen, these are the same BE-4 engines that will power United Launch Alliance’s new Vulcan rocket.”

A United Launch Alliance (ULA) Delta IV rocket carrying the WGS-7 mission for the U.S. Air Force launches from Cape Canaveral Air Force Station, Fl, on July 23, 2015. Credit: Ken Kremer/kenkremer.com
A United Launch Alliance (ULA) Delta IV rocket launching from Cape Canaveral Air Force Station, Fl, on July 23rd, 2015. Credit: Ken Kremer/kenkremer.com

The rocket will have a sea-level thrust of 1.746 million kg (3.85 million lbs), placing it ahead of the Delta IV Heavywhich has a sea-level thrust of about 900,000 kg (2 million lbs) – but behind the 2.268 million kg (5 million lbs) of the Falcon Heavy. Both variants will be powered by BE-4 engines, which are also manufactured by Blue Origin. The third-stage also employs a single vacuum-optimized BE-3 engine that burns liquid hydrogen and liquid oxygen.

However, the most interesting facet of the New Glenn is the fact that it will be reusable, with its first stage providing braking thrust and deployable legs (similar to the Falcon 9). In creating a heavy lift rocket that employs a retrievable first-stage, Blue Origin has signaled its intent to give SpaceX a run for its money when it comes to the development of reusable rocket technology.

It is also likely to raise the company’s profile, which has so far been limited to conducting sub-orbital research for NASA and dabbling in the space-tourism industry. But once the New Glenn is up and running, it is likely to begin securing contracts to provide resupply services the ISS, as well as contracts with companies and research institutions to place satellites in orbit.

The Falcon Heavy, once operational, will be the most powerful rocket in the world. Credit: spacex.com
The Falcon Heavy, once operational, will be the most powerful rocket in the world. Credit: spacex.com

According to The Verge, Bezos also hinted that his company has another project in mind – called the New Armstrong. While no details have been given just yet, the name of this rocket is a clear allusion to the Moon Landing, and hints that the company may have designs on possible moon missions in the coming decades.

This is an exciting time for the NewSpace industry. In the coming months, SpaceX is expected to conduct the first launch of the Falcon Heavy, which will be the most powerful rocket built in the US since the retirement of the Apollo program’s Saturn V launcher. And if they keep to their current schedule, Blue Origin will be following this in a few years time with the launch of the largest rocket of the post-Apollo era.

Big rockets and big lift capacities can mean only thing: big things lie ahead of us!

Further Reading: ArsTechnica, The Verge, Blue Origin

Stunning New Images Of Mars From The Curiosity Rover

Murray formation: rocks laid down by water and sculpted by wind
Finely layered rocks within the "Murray formation" layer of lower Mount Sharp on Mars. Credit: NASA

Since its deployment in 2012 to the surface of Mars, the Curiosity rover has sent back many breathtaking images of the Red Planet. In addition to snapping photos of the comet Siding Spring and Earth from the surface, not to mention some wonderful panoramic selfies, the rover has also taken countless images that show the geology and surface features of Mars’ in stunning detail.

And with the latest photos to be released by NASA, the Curiosity rover has provided us with a wonderful look at the “Murray Buttes” region, which is in the lower part of Mount Sharp. These images were taken by the Curiosity Mast Camera (Mastcam) on Sept. 8th, and provide some lovely insight into the geological history of the region.

Using these images, the Curiosity team hopes to assemble another impressive color mosaic that will give a detailed look at the region’s rocky, desert-like landscape. As you can see from the images provided, the region is characterized by mesas and buttes, which are the eroded remnants of ancient sandstone. Much like other spots around Mount Sharp, the area is of particular interest to the Curiosity team.

Sloping buttes and layered outcrops within the "Murray formation" layer of lower Mount Sharp. Credit: NASA
Sloping buttes and layered outcrops within the “Murray formation” layer of lower Mount Sharp. Credit: NASA

For years, scientists have understood that the rock layers that form the base of Mount Sharp accumulated as a result of sediment being deposited within the ancient lake bed billions of years ago. In this respect, the geological formations are similar to those found in the desert regions of the southwestern United States.

Ashwin Vasavada, the Curiosity Project Scientist of NASA’s Jet Propulsion Laboratory, told Universe Today via email:

” The Murray Buttes region of Mars is reminiscent of parts of the American southwest because of its butte and mesa landscape. In both areas, thick layers of sediment were deposited by wind and water, eventually resulting in a “layer cake” of bedrock that then began to erode away as conditions changed.  In both places, more resistant sandstone layers cap the mesas and buttes because they protect the more easily eroded, fine-grained rock underneath. 

“Like at Monument Valley near the Utah-Arizona border, at Murray Buttes there are just small remnants of these layers that once covered the surface more completely.  There were wind-driven sand dunes at both places, too, that now appear as cross-bedded sandstone layers.  There are of course many differences between Mars and the American Southwest.  For example, there were large inland seas in the Southwest, while at Gale crater there were lakes.”

These sediment layers are believed to have been laid down over the course of 2 billion years, and may have completely filled the crater at one time. Since it is widely believed that lakes and streams existed in the Gale Crater 3.3 – 3.8 billion years ago, some of the lower sediment layers may have originally been deposited on a lake bed.

A hillside outcrop with finely layered rocks within the "Murray formation" layer of lower Mount Sharp. Credit: NASA
A hillside outcrop with finely layered rocks within the “Murray formation” layer of lower Mount Sharp. Credit: NASA

For this reason, the Curiosity team also took drill samples from the Murray Buttes area for analysis. This began on Sept. 9th, after the rover was finished taking pictures of the area. As Vasavada explained:

“The Curiosity team is drilling regularly as the rover ascends Mount Sharp. We are drilling into the fine-grained rock that was deposited within lakes in order to see how the lake chemistry, and therefore the environment, changed over time. Curiosity drilled into the coarser sandstone that forms the upper layers of the buttes when the rover crossed the Naukluft Plateau earlier in 2016.”

After the drilling is completed, Curiosity will continue farther south and higher up Mount Sharp, leaving behind these spectacular formations. These pictures represent Curiosity‘s last stop in the Murray Buttes, where the rover has been spending the past month.

And as of this past September 11th, 2016, Curiosity has been on the planet Mars for a total of 4 years and 36 days (or 1497 Earth days; 1458 sols) since it landed on August 6th, 2012.

One has to wonder how the pareidolia folks are going to interpret these ones. After “seeing” a rat, a lizard, a doughnut, a coffin, and so forth, what’s left? Might I suggest that the top image kind of looks like a statue-column?

Further Reading: NASA – Solar System Exploration