Universe Today

August 3, 2009December 24, 2015 by Nancy Atkinson

Chandrayaan’s M3 Looks Back At Earth

This false-color image of Earth was taken from 200 kilometers (124 miles) above the lunar surface was taken by the Moon Mineralogy Mapper, one of two NASA instruments onboard the Indian Space Research Organization's Chandrayaan-1 spacecraft. Credit: NASA/JPL/Brown

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It’s a little fuzzy, but considering the camera was meant to capture the surface of the Moon from 200 kilometers (124 miles) away rather than Earth at 360,000 km (224,000 miles), it’s not bad. This image was taken by NASA’s Moon Mineralogy Mapper (M3 – M Cubed), on board the Indian Space Research Organization’s Chandrayaan-1 spacecraft orbiting the Moon. Australia is visible in the lower center of the image. The image is presented as a false-color composite with oceans a dark blue, clouds white, and vegetation an enhanced green. The image data were acquired on July 22, 2009.

The Moon Mineralogy Mapper instrument is a state-of-the-art imaging spectrometer designed to provide the first map of the entire lunar surface at high spatial and spectral resolution. Scientists will use this information to answer questions about the moon’s origin and development and the evolution of terrestrial planets in the early solar system. Future astronauts will use it to locate resources, possibly including water, that can support exploration of the moon and beyond.

Taking an image of Earth, well, that’s just showing off!

Source: JPL

August 3, 2009December 24, 2015 by Nancy Atkinson

How Many Galaxies Have We Discovered?

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Astronomers think that there are hundreds of billions galaxies in the universe, however the exact number is not known. But astronomers should know how many galaxies we’ve actually seen and discovered, right? Well, not necessarily. “We don’t know,” says Ed Churchwell, professor of astronomy at the University of Wisconsin-Madison. “We know it’s a very large number.” In just one image for example, the Hubble Ultra Deep Field, above, there are about 10,000 galaxies visible.

In our own galaxy, There are between ~~4 billion~~ 100-300 billion stars in the Milky Way. At most, 8,479 of them are visible from Earth. Roughly 2,500 stars are available to the unaided eye in ideal conditions from a single spot at a given time.

But the number of galaxies will keep growing as our telescopes get better and can look out and back farther in time.

“To count them all, you have to be able to look far enough back in time or deep enough in space to see when galaxies were formed,” Churchwell says. “We haven’t reached that point yet. It’s not a well-determined number, but at some point we’re going to reach it.”

The estimate of how many galaxies there are in the universe is done by counting how many galaxies we can see in a small area of the sky. This number is then used to guess how many galaxies there are in the entire sky.

For the time being, the hundreds of billions in the tally are extrapolated from the Hubble Ultra Deep Field, taken over a time period in 2003 and 2004. Pointed at a single piece of space for several months — a spot covering less than one-tenth of one-millionth of the sky — Hubble returned an image of galaxies 13 billion light years away.

“You look at that and say, ‘How many galaxies can I see?’” Churchwell explains. “And that turns out to be a very large number.”

“Then you take that number of galaxies from that postage-stamp-sized piece of the sky and multiply it by the number of postage-stamp-sized pieces of sky,” Churchwell says. “And that turns out to be a much larger number.”

In the first Hubble Deep Field image, taken in 1995, there are about 3,000 galaxies visible in the image.

Source: UW-M

August 3, 2009December 24, 2015 by Nancy Atkinson

Astro Art of the Week: Dragon Vs. Eagle

Dragon Vs. Eagle. Credit: Wienie van der Oord

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Here’s the fourth installment of our new feature, showcasing our readers’ prowess with image editing software. This week’s Astro Art of the Week is a showdown of cosmic proportions: “Dragon Versus Eagle” was submitted by Wienie van der Oord from Negev Desert in Israel.

The image of the Eagle Nebula was taken by Wienie’s friend, Kfir Simon, with a DSI 3 pro, HAlpha filter and a Canon with 200mm lens. You can see more of Kfir’s astrophotography here. . Thanks Wienie and Kfir!

Also, we’re still contemplating a good title for this feature. We’ve tried “Astro ‘Shop of the Week,” (as in ‘Photoshop’) and now “Astro Art of the Week.” If you have any suggestions for a good title, post it in the comment section. Thanks!

August 3, 2009December 29, 2015 by Nancy Atkinson

Carnival of Space #114: Third Cheapest Carnival on Earth

This week’s Carnival of Space is hosted by Steve Nerlich at Cheap Astronomy

Click here to read the Carnival of Space #114.

And if you’re interested in looking back, here’s an archive to all the past Carnivals of Space. If you’ve got a space-related blog, you should really join the carnival. Just email an entry to [email protected], and the next host will link to it. It will help get awareness out there about your writing, help you meet others in the space community – and community is what blogging is all about. And if you really want to help out, let Fraser know if you can be a host, and he’ll schedule you into the calendar.

Finally, if you run a space-related blog, please post a link to the Carnival of Space. Help us get the word out.

August 2, 2009December 24, 2015 by Nancy Atkinson

Orbiting Toolbag Will Enter Atmosphere Aug. 3

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The most famous toolbag in the world (and space) will soon be no more. The ISS Toolbag will enter Earth’s atmosphere and completely burn up. Current estimates say the toolbag should become a fireball on August 3 around 1316 Universal Time. It should be visible over the Pacific Ocean west of Mexico (12.7° N, 257.1° E). Astronaut Heidemarie Stefanyshyn-Piper dropped the backpack-sized kit on Nov. 18, 2008, while she was working outside the International Space Station. Since then the toolbag has circled Earth over 4,000 times, and has even been visible from the ground. Keep track of the toolbag at Heaven’s Above or on SpaceWeather.com’s Satellite Tracker.

August 2, 2009December 24, 2015 by Abby Cessna

Giant Planets

Jupiter, seen by Cassini. Image credit: NASA/JPL

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While the inner four planets seem large, they are nothing compared to the four outer planets, which are also known as gas giants or Jovian planets. The four giant planets in our Solar System are Jupiter, Saturn, Uranus, and Neptune.

Jupiter is the largest planet in our Solar System, and it truly is a giant planet. Jupiter is so large that you could fit 1321 Earths inside the planet. It is a gas giant, which means that it is comprised almost entirely of gas with a liquid core of heavy metals. Since none of the gas giants has a solid surface, you cannot stand on any of these planets, nor can spacecraft land on them. Another common characteristic of the giant planets is that they all have dozens of moons. In fact, Jupiter has 63 moons that have been discovered so far.

All of the giant planets in our Solar System have rings, but Saturn’s rings are by far the most famous of any. This planet’s ring system is composed of rock, dust, and other particles. The other planetary ring systems are made of similar elements.

Uranus and Neptune are also gas giants, but instead of just helium and hydrogen, they also have significant amounts of ices in their atmospheres. These ices include water, methane, and ammonia. It is the methane in the atmospheres of Uranus and Neptune that give the planets their blue color. Uranus and Neptune are also known as ice giants because of the proportion of ices in their atmospheres.

Giant planets are not limited to our Solar System either. In fact, astronomers have discovered many Jupiter-like planets in other solar systems. For example, in 2007, a group of British astronomers discovered three gas giants that are heavier than Jupiter is. These gas giants are much closer to their star than our Solar System’s gas giants are to the Sun. Scientists think that this may be one reason why these extrasolar planets are heavier, suggesting that only heavier planets can survive closer to a star. Because these planets are so much closer to their sun, they are much hotter than Jupiter and our Solar System’s other gas giants are.

These are just a handful of the gas giants discovered in different solar systems. Astronomers have discovered other extrasolar planets much bigger than Jupiter. Since all of the first extrasolar planets found were gas giants similar to Jupiter, astronomers began to despair of ever finding Earth-like planets that could support life. Recently though, astronomers have discovered different types of extrasolar planets, raising their hopes of finding life on other planets.

Universe Today has a number of articles to check out on gas giants and how big planets get.

You should also take a look at these articles on gas giants and British scientists discover giant planets hotter and heavier than Jupiter.

Astronomy Cast has an episode on extrasolar planets, hot Jupiters, and pulsar planets you should not miss.

August 2, 2009December 24, 2015 by Abby Cessna

Beyond the Solar System

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You are probably somewhat familiar with our Solar System. At least you most likely know that there are eight planets in it, including the Earth, the Sun, moons, and a number of other objects like Pluto and asteroids. However, there is a lot more beyond the Solar System of which you may not be aware.

Our galaxy is the Milky Way Galaxy, but there are also other ones including the Andromeda Galaxy. Each galaxy is a system composed of different star systems, stellar remains, and interstellar medium. Although astronomers are not certain, they estimate that there are one hundred billion galaxies in the universe. Between the galaxies is intergalactic space, which has a thin gas in it. It is no wonder that the universe is considered to be infinite when you consider how large our Solar System is and that this Solar System is just one of many in our galaxy. This really puts into perspective exactly how small the Earth, and we, are in the big picture.

The Milky Way galaxy has many stars in it. Beyond our Solar System is interstellar medium and more stars along with their star systems. Interstellar medium is the vacuum of space between different star systems, although the space is not actually an empty vacuum. It has dust and other particles in it in addition to cosmic rays and magnetic fields.

Astronomers have already discovered many extrasolar planets – planets beyond our Solar System that orbit stars other than our own. The first extrasolar planet’s existence was not confirmed until 1995, because technology was not advanced enough to detect these distant planets. Since then, 357 extrasolar planets, also known as exoplanets, have been discovered. It is estimated that only a small percentage of stars have planets, and most of these stars are similar to our own Sun.

At first, the only extrasolar planets that astronomers could find were gas giants similar to Jupiter. However, in recent years, they have found planets similar to Neptune. This strengthened the hope of astronomers who were looking for Earth-like planets. In fact, some astronomers believe that they have found Earth-like planets in the past few years. Astronomers are still trying to find a way to determine whether there is life on these planets.

While there is still much more to learn in our own Solar System – the Moon is the only place besides Earth humans have actually set foot – there are also many things to discover beyond our Solar System. Not just other stars, but also other galaxies if we can reach them.

Universe Today has articles on finding a cyclops galaxy and astronomers could detect oceans on extrasolar planets.

For more information, try lightest exoplanet discovered and top 10 most intriguing extrasolar planets.

Astronomy Cast has an episode that deals with the extrasolar planets.

References:
NASA: Milky Way Galaxy
NASA Science

August 2, 2009December 24, 2015 by Abby Cessna

All the Planets

This is a picture of the sequence of the eight planets and three of the dwarf planets. Image courtesy of IAU.

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Since 2006, due to a controversial decision by the International Astronomical Union (IAU) that demoted Pluto to a dwarf planet, we have had eight planets.

Mercury is a small planet, which can reach extreme temperatures. Since the planet is the closest one to the Sun, it can reach temperatures of 450°C. However, because the planet has almost no atmosphere due to very little gravity, the surface also drops to low temperatures of -170°C.

Venus is farther from the Sun than Mercury is, but it stays hotter due to its thick, toxic atmosphere. The main compound in Venus’ atmosphere is carbon dioxide, which creates the strongest greenhouse effect of any planet.

Undoubtedly, you already know a lot about Earth, but you may not know that our planet is the only one in our Solar System that has plate tectonics. The Earth’s outer crust is broken up into various sections called plates, which can move. These plates also take carbon out of the atmosphere and recycle it. This prevents a greenhouse effect like Venus’ and keeps the Earth from getting too hot. This is just one feature of our unique planet that helps support life.

Mars is the only inner planet, except for Earth, that has moons. Its two moons are called Phobos and Deimos. In Greek mythology, Phobos is a son of Ares (the equivalent of Mars) and Deimos is a figure that represents dread.

Jupiter is the model for gas giants as well as being the largest planet in our Solar System. It was named after the Roman king of the gods who was also the god of the sky and of thunder, which is fitting considering its size. Jupiter has 63 moons – more than any other planet in our Solar System.

Saturn is the only planet in our Solar System that has an average density less than water. Its core is actually denser than water, but its gas atmosphere balances the heavier core. You may consider floating Saturn in water, but even if you found a planet with a large enough body of water, the gases that make up Saturn’s atmosphere would simply merge with the other planet’s atmosphere.

Uranus and Neptune both belong to a class of gas giants called ice giants because they contain higher amounts of “ices” in their atmosphere. These ices include water, ammonia, and methane.

Neptune is an ice giant with the fastest winds of any planets. These winds can reach speeds of 2,100 kilometers per hour. The planet was discovered with mathematical predictions when astronomers noticed discrepancies in Uranus’ orbit.

Universe Today has many articles on the planets including order of the planets and planets in the Solar System.

If you are looking for more information, try all about the planets and an overview of the planets.

Astronomy Cast has episodes on all the planets including Jupiter.

August 2, 2009March 25, 2012 by Nancy Atkinson

A Plethora of Recent Astronomy Cast Offerings

Fraser and Pamela recently unleashed their astronomical prowess in a big way with five new episodes of Astronomy Cast. Included are some very thought-provoking topics like astrobiology, space elevators and interstellar travel, not to mention a whole host of other topics covered in a couple of questions shows. So, here’s a chance to immerse yourself in Astronomy Cast!

Episode # 145: Interstellar Travel

Questions Show: Imaging Extrasolar Planets, Infinite Universe, Inside a Black Hole

Episode # 144: Space Elevators

Questions Show: Matter Balance, Jumping Light Speed, and Black Hole Star Formation

Episode # 143: Astrobiology

August 1, 2009November 1, 2016 by Nancy Atkinson

Opportunity Spies Unusual Rock — Large Meteorite?

'Block Island,' an odd-shaped, dark rock, which may be a meteorite. Credit: NASA/JPL

The Opportunity rover has come across an odd-shaped, large, dark rock, about 0.6 meters (2 feet) across on the surface of Mars, which may be a meteorite. The rover team spotted the rock called “Block Island,” on July 18, 2009, in the opposite direction from which it was driving. The team then had the rover do a hard right (not really, but you know what I mean) and backtrack some 250 meters (820 feet) to study it closer. Oppy has been studying the rock with its alpha particle X-ray spectrometer to get composition measurements and to confirm if indeed it is a meteorite.

Below, see a close-up, colorized version of Block Island and a 3-D version, both created by Photoshopper Extraordinaire Stu Atkinson.

Block Island close up and colorized. Credit: NASA/JPL, with image editing by Stuart Atkinson

Block Island really does have a meteorite-like look to it. Stu suggested on his blog that it looks like several meteorites found on Earth, such as one of the Derrick Peak meteorites found in Antarctica, shown below. The Derrick Peak meteorites are iron meteorites, and about 27 were found in one location in Antarctica. Researchers believe they all came from one meteor shower.

Check out Stu’s blog Cumbrian Sky to see lots of other meteorites, including the one Opportunity found on Mars in 2005.

And below is a look at Block Island in 3-D. We’ll keep you posted on the results from Oppy’s examinations of this rock, and what this interesting find might tell us.

Block Island in 3-D. Credit: JPL, NASA and Stu Atkinson

Sources: JPL, Cumbrian Sky