Artist's impression of a system of exoplanets orbiting a low mass, red dwarf star. Credit: NASA/JPL
Studies of low-mass, ultra-cool and ultra-dim red dwarf stars have turned up a wealth of extra-solar planets lately. These include the discoveries of a rocky planet orbiting the closest star to the Solar System (Proxima b) and a seven-planet system just 40 light years away (TRAPPIST-1). In the past few years, astronomers have also detected candidates orbiting the stars Gliese 581, Innes Star, Kepler 42, Gliese 832, Gliese 667, Gliese 3293, and others.
The majority of these planets have been terrestrial (i.e. rocky) in nature, and many were found to orbit within their star’s habitable zone (aka. “goldilocks zone”). However the question whether or not these planets are tidally-locked, where one face is constantly facing towards their star has been an ongoing one. And according to a new study from the University of Washington, tidally-locked planets may be more common than previously thought.
The study – which is available online under the title “Tidal Locking of Habitable Exoplanets” – was led by Rory Barnes, an assistant professor of astronomy and astrobiology at the University of Washington. Also a theorist with the Virtual Planetary Laboratory, his research is focused on the formation and evolution of planets that orbit in and around the “habitable zones” of low-mass stars.
Tidal locking results in the Moon rotating about its axis in about the same time it takes to orbit the Earth (left side). Credit: Wikipedia
For modern astronomers, tidal-locking is a well-understood phenomena. It occurs as a result of their being no net transfer of angular momentum between an astronomical body and the body it orbits. In other words, the orbiting body’s orbital period matches its rotational period, ensuring that the same side of this body is always facing towards the planet or star it orbits.
Consider Earth’s only satellite – the Moon. In addition to taking 27.32 days to orbit Earth, the Moon also takes 27.32 days to rotate once on its axis. This is why the Moon always presents the same “face” towards Earth, while the side that faces away is known as the “dark side”. Astronomers believe this became the case after a Mars-sized object (Theia) collided with Earth some 4.5 billion years ago.
Aside from throwing up debris that would eventually form the Moon, the impact is believed to have struck Earth at such an angle that it gave our planet an initial rotation period of 12 hours. In the past, researchers have used this 12-hour estimation of Earth’s rotation as a model for exoplanet behavior. However, prior to Barnes’ study, no systematic examinations had ever been conducted.
Looking to address this, Barnes chose to address the long-held assumption that only smaller, dimmer stars could host orbiting planets that were tidally locked. He also considered other possibilities, which included slower or faster initial rotation periods as well as variations in planet size and the eccentricity of their orbits. What he found was that previous studies had been rather limited and only made allowances for one outcome.
Tidally-locked, rocky planets are common around low-mass, M-type (red dwarf) stars, due to their close orbits. Credit: M. Weiss/CfA
As he explained in a University of Washington press statement:
“Planetary formation models, however, suggest the initial rotation of a planet could be much larger than several hours, perhaps even several weeks. And so when you explore that range, what you find is that there’s a possibility for a lot more exoplanets to be tidally locked. For example, if Earth formed with no Moon and with an initial ‘day’ that was four days long, one model predicts Earth would be tidally locked to the sun by now.”
From this, he found that potentially-habitable planets that orbit very late M-type (red dwarf) stars are likely to attain highly-circular orbits about 1 billion years after their formation. Furthermore, he found that for the majority, their orbits would be synchronized with their rotation – aka. they would be tidally-locked with their star. These findings could have significant implications for the study of exoplanets formation and evolution, not to mention habitability.
In the past, tidally-locked planets were thought to have extremes climates, thus eliminating any possibility of life. As an example, the planet Mercury experiences a 3:2 spin-orbit resonance, meaning it rotates three times on its axis for every two orbits it completes of the Sun. Because of this, a single day on Mercury lasts as long as 176 Earth days, and temperature range from 100 (-173 °C; -279 °F) to 700 K (427 °C; 800 °F) between the day side and the night side.
For a tidally-locked planets that orbit close to their stars, it was believed this situation would be even worse. However, astronomers have since come to speculate that the presence of an atmosphere around these planets could redistribute temperature across their surfaces. Unlike Mercury, which has no atmosphere and experiences no wind, these planets could maintain temperatures that would be supportive to life.
Artist’s impression of a “Earth-like” planet orbiting a nearby red dwarf star. Credit: ESO/M. Kornmesser/N. Risinger (skysurvey.org).
In any case, this study is one of many that is putting constraints on recent exoplanet discoveries. This is especially important given that the detection and study of extra-solar planets is still in its infancy, and limited to largely indirect methods. In other words, astronomers make estimates of a planet’s size, composition and whether or not it has an atmosphere based on transits and the influence these planets have on their stars.
In the coming years, next-generations missions like the James Web Space Telescope and the Transiting Exoplanet Survey Satellites (TESS) are expected to improve this situation drastically. In addition to conducting more detailed observations on existing discoveries, they are also expected to uncover a wealth of more planets. If Barnes’ study is correct, the majority of those found will be tidally-locked, but that need not mean they are uninhabitable.
Prof. Barnes paper was accepted for publication by the journal Celestial Mechanics and Dynamical Astronomy. The research was funded by a NASA grant through the Virtual Planetary Laboratory.
SpaceX launched its 12th resupply mission to the International Space Station from NASA's Kennedy Space Center in Florida at 12:31 p.m. EDT on Monday, Aug. 14, 2017. Credit: Ken Kremer/Kenkremer.com
SpaceX launched its 12th resupply mission to the International Space Station from NASA’s Kennedy Space Center in Florida at 12:31 p.m. EDT on Monday, Aug. 14, 2017. Credit: Ken Kremer/Kenkremer.com
KENNEDY SPACE CENTER, FL – Todays (Aug. 14) stunning SpaceX Space Station cargo delivery blastoff to the International Space Station (ISS) and flawless first stage landing from the Kennedy Space Center and Cape Canaveral Air Force Station in the Sunshine State kicked off a rapid fire sequence of liftoffs planned for mid August.
All 9 SpaceX Falcon 9 Merlin 1D first stage engines ignited precisely on time from seaside pad 39A at NASA’s Kennedy Space Center in Florida today (Aug. 14) at 12:31 p.m. EDT (1631 GMT).
“It was a gorgeous day and a specular launch,” said Dan Hartman, NASA deputy manager of the International Space Station Program, at the post launch briefing at the Kennedy Space Center press site.
The 9 Merlin 1D’s of the two stage 213-foot-tall (65-meter-tall) Falcon 9 generate 1.7 million pounds of liftoff thrust fueled by liquid oxygen and RP-1 propellants.
“Just greatness to report about the launch,” said Hans Koenigsmann, SpaceX vice president of Flight and Build Reliability at the post launch briefing.
“The second stage deployed Dragon to a near perfect orbit. The first stage was successful and made a perfect landing. From what I’ve heard, it’s right on the bullseye and made a very soft touchdown, so it’s a great pre-flown booster ready to go for the next time.”
So its 1 down and 2 launches to go along the Florida Space Coast over the next 11 days of manmade wonder – Plus a Total Solar ‘Eclipse Across America’ natural wonder sandwiched in between !!
SpaceX launched its 12th resupply mission to the International Space Station from NASA’s Kennedy Space Center in Florida at 12:31 p.m. EDT on Monday, Aug. 14, 2017. Credit: Ken Kremer/Kenkremer.com
Monday’s picture perfect lunchtime liftoff of the unmanned SpaceX CRS-12 Dragon cargo freighter bound for the ISS and loaded with over 3 tons of science, research hardware and supplies including a hefty cosmic ray detector named ISS-CREAM, medical research experiments dealing with Parkinson’s disease, lung and heart tissue, vegetable seeds, dozens of mice and much more – came off without a hitch.
“We’re excited that about three quarters of the payload aboard is science,” noted Hartman. “With the internal and external payloads that we have going up, it sets a new bar for the amount of research that we’ve been able to get on this flight.”
And all 6 astronauts and cosmonauts serving aboard the station are especially looking forward to unpacking and serving up a specially cooled and hefty stash of delicious ice cream!
The ice cream, medical experiments and mice were all part of the late load items added the evening before liftoff – work that was delayed due to thunderstorms and completed just in time to avoid a launch delay.
Launch of SpaceX Falcon on Dragon CRS-12 mission to the ISS from NASA’s Kennedy Space Center in Florida at 12:31 p.m. EDT on Monday, Aug. 14, 2017. Credit: Julian Leek
A huge crowd of delighted locals, tourists and folks flocking in from around the globe, packed local beaches, causeways and parks and the Kennedy Space Center and witnessed a space launch and landing spectacular they will long remember.
Ground landing of SpaceX Falcon 9 first stage at Landing Zone-1 (LZ-1) after SpaceX launched its 12th resupply mission to the International Space Station from NASA’s Kennedy Space Center in Florida from pad 39A at 12:31 p.m. EDT on Monday, Aug. 14, 2017. Credit: Ken Kremer/Kenkremer.com
The Dragon resupply ship dubbed Dragon CRS-12 counts as SpaceX’s twelfth contracted commercial resupply services (CRS) mission to the International Space Station for NASA since 2012.
The launch and landing of the SpaceX Falcon 9 booster took place just minutes apart under near perfect weather conditions, as the Dragon capsule sped to the heavens on a mission to the High Frontier of Space.
Ground landing of SpaceX Falcon 9 first stage at Landing Zone-1 (LZ-1) after SpaceX launched its 12th resupply mission to the International Space Station from NASA’s Kennedy Space Center in Florida from pad 39A at 12:31 p.m. EDT on Monday, Aug. 14, 2017. Credit: Ken Kremer/Kenkremer.com
The 22 story Falcon 9 roared off pad 39A on a stream of flames and exhaust into blue skies decorated with artfully spaced wispy clouds that enhanced the viewing experience as the rocket accelerated to orbit and on its way to the 6 person multinational crew.
The triple headed sunshine state space spectacular marches forward in barely 4 days with liftoff of NASA’s amazingly insectoid-looking TDRS-M science relay comsat slated for Friday morning Aug. 18 atop a United Launch Alliance (ULA) Atlas V rocket.
Lastly, a week after TDRS-M and just 11 days after the SpaceX Dragon an Orbital ATK Minotaur 4 rocket is due to blastoff just before midnight Aug. 25 and carry the ORS 5 mission to orbit for the U.S. military’s Operationally Responsive Space program. The Minotaur IV utilizes three stages from decommissioned Peacekeeper ICBMs formerly aimed at the Russians and perhaps the North Koreans.
The Total Solar ‘Eclipse Across America’ takes place on Monday, Aug. 21. It’s the first solar eclipse in 99 years that space the continent from coast to coast and will be at least partially visible in all 48 contiguous states!
The 20-foot high, 12-foot-diameter Dragon CRS-12 vessel is carrying more than 6,400 pounds (2,900 kg) of science experiments and research instruments, crew supplies, food water, clothing, hardware, gear and spare parts to the million pound orbiting laboratory complex.
20 mice are also onboard from NASA for the Rodent Research 9 (RR-9) experiment and another dozen from Japanese researchers. This will support more than 80 of the 250 research investigations and experiments being conducted by Expedition 52 and 53 crew members.
Dragon reached its preliminary orbit about 10 minutes later and successfully deployed its life giving solar arrays.
Dragon CRS-12 now begins a 2 day orbital chase of the station via a carefully choreographed series of thruster firings that bring the commercial spacecraft to rendezvous with the space station on Aug. 16.
Dragon will be grappled with the station’s 57.7-foot-long (17.6 meter-long) Canadian-built robotic arm at approximately 7 a.m. EDT on Aug. 16 by astronauts Jack Fischer of NASA and Paolo Nespoli of ESA (European Space Agency). It then will be installed on the Harmony module.
The Dragon spacecraft will spend approximately 35 days attached to the space station, returning to Earth in mid-September with over 3000 pounds of science samples and results gathered over many months from earlier experiments by the station crews.
Dragon CRS-12 is SpaceX’s third contracted resupply mission to launch this year for NASA.
The prior SpaceX cargo ships launched on Feb 19 and June 3, 2017 on the CRS-10 and CRS-11 missions to the space station. CRS-10 is further noteworthy as being the first SpaceX launch of a Falcon 9 from NASA’s historic pad 39A.
A fourth cargo Dragon is likely to launch this year in December on the CRS-13 resupply mission under NASA’s current plans.
SpaceX leased pad 39A from NASA in 2014 and after refurbishments placed the pad back in service this year for the first time since the retirement of the space shuttles in 2011.
Previous launches include 11 Apollo flights, the launch of the unmanned Skylab in 1973, 82 shuttle flights and five SpaceX launches.
Cargo Manifest for CRS-12:
TOTAL CARGO: 6415.4 lbs. / 2910 kg
TOTAL PRESSURIZED CARGO WITH PACKAGING: 3642 lbs. / 1652 kg
• Science Investigations 2019.4 lbs. / 916 kg
• Crew Supplies 485 lbs. / 220 kg
• Vehicle Hardware 747.4 lbs. / 339 kg
• Spacewalk Equipment 66.1 lbs. / 30 kg
• Computer Resources 116.8 lbs. / 53 kg
UNPRESSURIZED 2773.4 lbs. / 1258 kg
• Cosmic-Ray Energetics and Mass (CREAM) 2773.4 lbs. / 1258 kg
The CREAM instrument from the University of Maryland will be stowed for launch inside the Dragon’s unpressurized trunk. Astronauts will use the stations robotic arm to pluck it from the trunk and attach it to a US port on the exposed porch of the Japanese Experiment Module (JEM).
CREAM alone comprises almost half the payload weight.
The Cosmic-Ray Energetics and Mass investigation (CREAM) instrument from the University of Maryland, College Park involves placing a balloon-borne instrument aboard the International Space Station to measure the charges of cosmic rays over a period of three years. CREAM will be attached to the Japanese Experiment Module Exposed Facility. Existing CREAM hardware used for balloon flights. Credit: NASA
Here is a NASA description of CREAM:
The Cosmic Ray Energetics and Mass (CREAM) instrument will be attached to the Japanese Experiment Module Exposed Facility on the space station, and measure the charges of cosmic rays. The data collected from its three-year mission will address fundamental questions about the origins and histories of cosmic rays, building a stronger understanding of the basic structure of the universe.
The LRRK2 experiment seeks to grow larger crystals of the protein to investigate Parkinson’s disease and help develop new therapies:
Here is a NASA description of LRRK2:
The Dragon’s pressurized area includes an experiment to grow large crystals of leucine-rich repeat kinase 2 (LRRK2), a protein believed to be the greatest genetic contributor to Parkinson’s disease. Gravity keeps Earth-grown versions of this protein too small and too compact to study. This experiment, developed by the Michael J. Fox Foundation, Anatrace and Com-Pac International, will exploit the benefits of microgravity to grow larger, more perfectly-shaped LRRK2 crystals for analysis on Earth. Results from this study could help scientists better understand Parkinson’s and aid in the development of therapies.
Watch this Michael J. Fox video describing the LRRK2 crystallization experiment:
Watch for Ken’s continuing onsite CRS-12, TRDS-M, and ORS 5 and NASA mission reports direct from the Kennedy Space Center and Cape Canaveral Air Force Station, Florida.
Stay tuned here for Ken’s continuing Earth and Planetary science and human spaceflight news. Ken Kremer
SpaceX Falcon 9 rocket rests horizontally at Launch Complex 39A at the Kennedy Space Center on 13 Aug. 2017 while being processed for liftoff of the Dragon CRS-12 resupply mission to the International Space Station (ISS) slated for 14 Aug. 2017. Credit: Ken Kremer/Kenkremer.com
Hubble image of Messier 54, a globular cluster located in the Sagittarius Dwarf Galaxy. Credit: ESA/Hubble & NASA
Welcome back to Messier Monday! In our ongoing tribute to the great Tammy Plotner, we take a look at globular cluster known as Messier 54!
During 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 others would not make the same mistake he did. In time, this list (known as the Messier Catalog) would come to include 100 of the most fabulous objects in the night sky.
One of these objects is the globular cluster known as Messier 54. Located in the direction of the Sagittarius constellation, this cluster was once thought to be part of the Milky Way, located about 50,000 light years from Earth, In recent decades, astronomers have come to realize that it is actually part of the Sagittarius Dwarf Galaxy, located some 87,000 light-years away.
What You Are Looking At:
Running away from us at a speed of 142 kilometers per second, this compact globe of stars could be as wide as 150 light years in diameter and as far away as 87,400 light years. Wait… Hold the press… Almost 90 thousand light years? Yeah. Messier 54 isn’t part of our own Milky Way Galaxy!
In 1994 astronomers made a rather shocking discovery… this tough to resolve globular was actually part of the Sagittarius Dwarf Elliptical Galaxy. As Michael H. Siegal (et al) said in their study:
“As part of the ACS Survey of Galactic Globular Clusters, we present new Hubble Space Telescope photometry of the massive globular cluster M54 (NGC 6715) and the superposed core of the tidally disrupted Sagittarius (Sgr) dSph galaxy. Our deep (F606W ~ 26.5), high-precision photometry yields an unprecedentedly detailed color-magnitude diagram showing the extended blue horizontal branch and multiple main sequences of the M54+Sgr system. Multiple turnoffs indicate the presence of at least two intermediate-aged star formation epochs with 4 and 6 Gyr ages and [Fe/H]=-0.4 to -0.6. We also clearly show, for the first time, a prominent, ~2.3 Gyr old Sgr population of near-solar abundance. A trace population of even younger (~0.1-0.8 Gyr old), more metal-rich ([Fe/H]~0.6) stars is also indicated. The Sgr age-metallicity relation is consistent with a closed-box model and multiple (4-5) star formation bursts over the entire life of the satellite, including the time since Sgr began disrupting.”
Inside its compact depths lurk at least 82 known variable stars – 55 of which are the RR Lyrae type. But astronomers using the Hubble Space telescope have have also discovered there are two semi-regular red variables with periods of 77 and 101 days. Kevin Charles Schlaufman and Kenneth John Mighell of the National Optical Astronomy Observatory explained in their study:
“Most of our candidate variable stars are found on the PC1 images of the cluster center – a region where no variables have been reported by previous ground-based studies of variables in M54. These observations cannot be done from the ground, even with AO as there are far too many stars per resolution element in ground-based observations.”
The globular cluster Messier 54. Credit: NASA
But what other kinds of unusual stars could be discovered inside such distant cosmic stellar evolutionary laboratory? Try a phenomena known as blue hook stars! As Alfred Rosenberg (et al) said in their study:
“We present BV photometry centered on the globular cluster M54 (NGC 6715). The color-magnitude diagram clearly shows a blue horizontal branch extending anomalously beyond the zero-age horizontal-branch theoretical models. These kinds of horizontal-branch stars (also called “blue hook” stars), which go beyond the lower limit of the envelope mass of canonical horizontal-branch hot stars, have so far been known to exist in only a few globular clusters: NGC 2808, Omega Centauri (NGC 5139), NGC 6273, and NGC 6388. Those clusters, like M54, are among the most luminous in our Galaxy, indicating a possible correlation between the existence of these types of horizontal-branch stars and the total mass of the cluster. A gap in the observed horizontal branch of M54 around Teff = 27,000 K could be interpreted within the late helium flash theoretical scenario, which is a possible explanation for the origin of blue hook stars.”
But with the stars packaged together so tightly, even more has been bound to occur inside of Messier 54. As Tim Adams (et al) indicated in their study:
“We investigate a means of explaining the apparent paucity of red giant stars within post-core-collapse globular clusters. We propose that collisions between the red giants and binary systems can lead to the destruction of some proportion of the red giant population, by either knocking out the core of the red giant or by forming a common envelope system which will lead to the dissipation of the red giant envelope. Treating the red giant as two point masses, one for the core and another for the envelope (with an appropriate force law to take account of the distribution of mass), and the components of the binary system also treated as point masses, we utilize a four-body code to calculate the time-scales on which the collisions will occur. We then perform a series of smooth particle hydrodynamics runs to examine the details of mass transfer within the system. In addition, we show that collisions between single stars and red giants lead to the formation of a common envelope system which will destroy the red giant star. We find that low-velocity collision between binary systems and red giants can lead to the destruction of up to 13 per cent of the red giant population. This could help to explain the colour gradients observed in PCC globular clusters. We also find that there is the possibility that binary systems formed through both sorts of collision could eventually come into contact perhaps producing a population of cataclysmic variables.”
Messier 54, as imaged by the VLT Survey Telescope at ESO’s Paranal Observatory in northern Chile. Credit: ESO
But the discoveries haven’t ended yet…. Because 2009 studies have revealed evidence for an intermediate mass black hole inside Messier 54 – the first known to have ever been discovered in a globular cluster.
“We report the detection of a stellar density cusp and a velocity dispersion increase in the center of the globular cluster M54, located at the center of the Sagittarius dwarf galaxy (Sgr). The central line-of-sight velocity dispersion is 20.2 ± 0.7 km s-1, decreasing to 16.4 ± 0.4 km s-1 at 2farcs5 (0.3 pc). Modeling the kinematics and surface density profiles as the sum of a King model and a point-mass yields a black hole mass of ~9400 M sun.” says R. Ibata (et al), “However, the observations can alternatively be explained if the cusp stars possess moderate radial anisotropy. A Jeans analysis of the Sgr nucleus reveals a strong tangential anisotropy, probably a relic from the formation of the system.”
History of Observation:
On July 24, 1778 when Charles Messier first laid eyes on this faint fuzzy, he had no clue that he was about to discover the very first extra-galactic globular cluster. In his notes he writes: “Very faint nebula, discovered in Sagittarius; its center is brilliant and it contains no star, seen with an achromatic telescope of 3.5 feet. Its position has been determined from Zeta Sagittarii, of 3rd magnitude.”
Years later Sir William Herschel would also study M54, and in his private notes he writes: “A round, resolvable nebula. Very bright in the middle and the brightness diminishing gradually, about 2 1/2′ or 3′ in diameter. 240 shews too pretty large stars in the faint part of the nebulosity, but I rather suppose them to have no connection with the nebula. I believe it to be no other than a miniature cluster of very compressed stars.”
Countless other observations would follow as the M54 became cataloged by other astronomers and each would in turn describe it only as having a much brighter core and some resolution around the edges. Have fun trying to crack this one!
Locating Messier 54:
M54 isn’t hard to find… Just skip down to Zeta Sagittarii, the southwestern-most star of Sagittarius “teapot” and hop a half degree south and a finger width (1.5 degrees) west. The problem is seeing it! In small optics, such as binoculars or a finder scope, it will appear almost stellar because of its small size. However, if you just look for what appears like a larger, dim star that won’t quite come into perfect focus, then you’ve found it.
In smaller telescopes, you’ll get no resolution on this class III globular cluster because it is so dense. Large aperture doesn’t fare much better either, with only some individual stars making their appearance at the outer perimeters. Because of magnitude and size, Messier 54 is better suited to dark sky conditions.
The location of Messier 54 in the Sagittarius constellation. Credit: IAU/Sky & Telescope magazine (Roger Sinnott & Rick Fienberg)
And here are the quick facts on this Messier Object to help you get started:
Object Name: Messier 54 Alternative Designations: M54, NGC 6715 Object Type: Class III Extragalactic Globular Cluster Constellation: Sagittarius Right Ascension: 18 : 55.1 (h:m) Declination: -30 : 29 (deg:m) Distance: 87.4 (kly) Visual Brightness: 7.6 (mag) Apparent Dimension: 12.0 (arc min)
Most exoplanets orbit red dwarf stars because they're the most plentiful stars. This is an artist's illustration of what the TRAPPIST-1 system might look like from a vantage point near planet TRAPPIST-1f (at right). Credits: NASA/JPL-Caltech
In February of 2017, a team of European astronomers announced the discovery of a seven-planet system orbiting the nearby star TRAPPIST-1. Aside from the fact that all seven planets were rocky, there was the added bonus of three of them orbiting within TRAPPIST-1’s habitable zone. As such, multiple studies have been conducted that have sought to determine whether or not any planets in the system could be habitable.
When it comes to habitability studies, one of the key factors to consider is the age of the star system. Basically, young stars have a tendency to flare up and release harmful bursts of radiation while planets that orbit older stars have been subject to radiation for longer periods of time. Thanks to a new study by a pair of astronomers, it is now known that the TRAPPIST-1 system is twice as old as the Solar System.
SpaceX Falcon 9 rocket rests horizontally at Launch Complex 39A at the Kennedy Space Center on 13 Aug. 2017 while being processed for liftoff of the Dragon CRS-12 resupply mission to the International Space Station (ISS) slated for 14 Aug. 2017. Credit: Ken Kremer/Kenkremer.com
SpaceX Falcon 9 rocket rests horizontally at Launch Complex 39A at the Kennedy Space Center on 13 Aug. 2017 while being processed for liftoff of the Dragon CRS-12 resupply mission to the International Space Station (ISS) slated for 14 Aug. 2017. Credit: Ken Kremer/Kenkremer.com
KENNEDY SPACE CENTER, FL – A triad of August liftoffs from the Florida Space Coast inaugurates Monday, Aug. 14 with a science laden commercial SpaceXDragon bound for the International Space Station (ISS) – loaded with over 3 tons of NASA science, hardware and supplies including a cosmic ray detector, medical research experiments dealing with Parkinson’s disease and lung tissue, vegetable seeds, mice and much more, following a successful engine test firing of the Falcon 9 booster on Thursday.
“Static fire test of Falcon 9 complete,” SpaceX confirmed via Twitter soon after completion of the test at 9:10 a.m. EDT, Aug 10. (1310 GMT) “—targeting August 14 launch from Pad 39A for Dragon’s next resupply mission to the @Space_Station.”
Check out our photos & videos herein of the Aug. 10 static first test of the Falcon 9 first stage that paves the path to blastoff – as witnessed live by Ken Kremer and Jeff Seibert.
The triple headed sunshine state space spectacular kicks off with Monday’s lunchtime launch of the next unmanned SpaceX Dragon cargo freighter to the ISS from seaside pad 39A at NASA’s Kennedy Space Center in Florida, now targeted for Aug. 14 at 12:31 p.m. EDT (1631 GMT).
Lastly, a week after TDRS-M and just 11 days after the SpaceX Dragon an Orbital ATK Minotaur 4 rocket is due to blastoff just before midnight Aug. 25 and carry the ORS 5 mission to orbit for the U.S. military’s Operationally Responsive Space program. The Minotaur IV utilizes three stages from decommissioned Peacekeeper ICBMs formerly aimed at the Russians.
Of course getting 3 rockets off the ground from 3 different companies is all highly dependent on Florida’s hugely fickle hurricane season weather and the ever present reality of potential technical glitches, errant boaters and more – possibly resulting in a domino effect of cascading launch scrubs.
And sandwiched in between the Florida Space Coast blastoffs is the Total Solar ‘Eclipse Across America’ on Monday, Aug. 21 – for the first time in 99 years!
Although KSC and central Florida are not within the path of totality, the sun will still be about 85% obscured by the Moon.
So if you’re looking for bang for the space buck, the next two weeks have a lot to offer space and astronomy enthusiasts.
1st Reused SpaceX Dragon cargo craft lifts off from Launch Complex 39A at NASA’s Kennedy Space Center in Florida at 5:07 p.m. June 3, 2017 on CRS-11 mission carrying 3 tons of research equipment, cargo and supplies to the International Space Station. Credit: Ken Kremer/kenkremer.com
The Dragon resupply ship dubbed Dragon CRS-12 counts as SpaceX’s twelfth contracted commercial resupply services (CRS) mission to the International Space Station for NASA since 2012.
SpaceX conducts successful static fire test of the Falcon 9 rocket on Aug. 10, 2017 at Launch Complex 39A on NASA’s Kennedy Space Center, Fl as seen from Playalinda causeway. Liftoff of the uncrewed Dragon CRS-12 resupply mission for NASA to the International Space Station (ISS) is scheduled for Aug. 14, 2017. Credit: Ken Kremer/kenkremer.com
Watch this video of the Aug. 10 static hotfire test:
Video Caption: Hot fire test of the SpaceX Falcon 9 rocket in preparation for it launching the NASA CRS-12 Dragon resupply mission to the International Space Station from Pad 39A at Kennedy Space Center in Florida. Credit: Jeff Seibert/AmericaSpace
The 20-foot high, 12-foot-diameter Dragon CRS-12 vessel is carrying more than 6,400 pounds ( 2,900 kg) of science experiments and research instruments, crew supplies, food water, clothing, hardware, gear and spare parts to the million pound orbiting laboratory complex. 20 mice are also onboard. This will support dozens of the 250 research investigations and experiments being conducted by Expedition 52 and 53 crew members.
SpaceX conducts successful static fire test of the Falcon 9 rocket on Aug. 10, 2017 at Launch Complex 39A on NASA’s Kennedy Space Center, Fl as seen from Playalinda causeway. Liftoff of the uncrewed Dragon CRS-12 resupply mission for NASA to the International Space Station (ISS) is scheduled for Aug. 14, 2017. Credit: Ken Kremer/kenkremer.com
If you can’t personally be here to witness the launch in Florida, you can always watch NASA’s live coverage on NASA Television and the agency’s website.
The SpaceX/Dragon CRS-12 launch coverage will be broadcast on NASA TV beginning noon on Aug. 14 with additional commentary on the NASA launch blog.
SpaceX will also offer their own live webcast beginning approximately 15 minutes before launch at about 12:16 p.m. EDT.
You can watch the launch live at NASA TV at – http://www.nasa.gov/nasatv
You can also watch the launch live at SpaceX hosted Webcast at – spacex.com/webcast
In the event of delay for any reason, the next launch opportunity is Tuesday, Aug. 15 with NASA TV coverage starting about 11:30 a.m. EDT.
The weather looks decent at this time with a 70% chance of favorable conditions at launch time according to U.S. Air Force meteorologists with the 45th Space Wing Weather Squadron at Patrick Air Force Base. The primary concerns on Aug. 14 are cumulus clouds and the potential for precipitation in the flight path.
The odds remain at 70% favorable for the 24 hour scrub turnaround day on Aug. 15.
Everything is currently on track for Monday’s noontime launch of the 230 foot tall SpaceX Falcon 9 on the NASA contracted SpaceX CRS-12 resupply mission to the million pound orbiting lab complex.
However since the launch window is instantaneous there is no margin for error. In case any delays arise during the countdown due to technical or weather issues a 24 hour scrub to Tuesday will result.
The lunchtime launch coincidently offers a convenient and spectacular opportunity for fun for the whole family as space enthusiasts flock in from around the globe.
Plus SpaceX will attempt a land landing of the 156 foot tall first stage back at the Cape at Landing Zone 1 some 8 minutes after liftoff – thus a double whammy of space action !!– punctuated by multiple loud sonic booms at booster landing time that will figuratively knock your socks off.
SpaceX Falcon 9 booster deploys quartet of landing legs moments before precision propulsive ground touchdown at Landing Zone 1 on Canaveral Air Force Station barely nine minutes after liftoff from Launch Complex 39A on 3 June 2017 from the Kennedy Space Center in Florida on the Dragon CRS-11 resupply mission to the International Space Station for NASA. Credit: Ken Kremer/Kenkremer.com
To date SpaceX has successfully recovered 13 boosters; 5 by land and 8 by sea, over the past 18 months. It’s a feat straight out of science fiction but aimed at drastically slashing the high cost of access to space.
The recent BulgariaSat-1 and Iridium-2 missions counted as the eighth and ninth SpaceX launches of 2017.
CRS-12 marks the eleventh SpaceX launch of 2017 and will establish a new single year record.
In contrast to the prior CRS-11 mission which flew a recycled Dragon, the CRS-12 Dragon is newly built.
The CRS-12 Dragon will be the last newly built one, says NASA. The remaining SpaceX CRS mission will utilize reused spaceships.
The Falcon 9 is also new and will attempt a land landing back at the Cape at Landing Zone-1 (LZ-1).
If the Aug. 14 launch occurs as scheduled, the Dragon will reach its preliminary orbit about 10 minutes later and deploy its life giving solar arrays. Dragon then begins a 2 day orbital chase of the station via a carefully choreographed series of thruster firings that bring the commercial spacecraft to rendezvous with the space station on Aug. 16.
Dragon will be grappled with the station’s Canadian built robotic arm at approximately 7 a.m. EDT on Aug. 16 by astronauts Jack Fischer of NASA and Paolo Nespoli of ESA (European Space Agency). It then will be installed on the Harmony module.
The Dragon spacecraft will spend approximately one month attached to the space station, returning to Earth in mid-September with results of earlier experiments.
Dragon CRS-12 is SpaceX’s third contracted resupply mission to launch this year for NASA.
The prior SpaceX cargo ships launched on Feb 19 and June 3, 2017 on the CRS-10 and CRS-11 missions to the space station. CRS-10 is further noteworthy as being the first SpaceX launch of a Falcon 9 from NASA’s historic pad 39A.
SpaceX leased pad 39A from NASA in 2014 and after refurbishments placed the pad back in service this year for the first time since the retirement of the space shuttles in 2011.
Previous launches include 11 Apollo flights, the launch of the unmanned Skylab in 1973, 82 shuttle flights and five SpaceX launches.
Cargo Manifest for CRS-12:
TOTAL CARGO: 6415.4 lbs. / 2910 kg
TOTAL PRESSURIZED CARGO WITH PACKAGING: 3642 lbs. / 1652 kg
• Science Investigations 2019.4 lbs. / 916 kg
• Crew Supplies 485 lbs. / 220 kg
• Vehicle Hardware 747.4 lbs. / 339 kg
• Spacewalk Equipment 66.1 lbs. / 30 kg
• Computer Resources 116.8 lbs. / 53 kg
UNPRESSURIZED 2773.4 lbs. / 1258 kg
• Cosmic-Ray Energetics and Mass (CREAM) 2773.4 lbs. / 1258 kg
The CREAM instrument from the University of Maryland will be stowed for launch inside the Dragon’s unpressurized trunk. Astronauts will use the stations robotic arm to pluck it from the trunk and attach it to the exposed porch of the Japanese Experiment Module (JEM).
The Cosmic-Ray Energetics and Mass investigation (CREAM) instrument from the University of Maryland, College Park involves placing a balloon-borne instrument aboard the International Space Station to measure the charges of cosmic rays over a period of three years. CREAM will be attached to the Japanese Experiment Module Exposed Facility. Existing CREAM hardware used for balloon flights. Credit: NASA
Here is a NASA description of CREAM:
The Cosmic Ray Energetics and Mass (CREAM) instrument, attached to the Japanese Experiment Module Exposed Facility, measures the charges of cosmic rays ranging from hydrogen to iron nuclei. The data collected from the CREAM instrument will be used to address fundamental science questions on the origins and history of cosmic rays. CREAM’s three-year mission will help the scientific community build a stronger understanding of the fundamental structure of the universe.
The LRRK2 experiment seeks to grow larger crystals of the protein to investigate Parkinson’s disease and help develop new therapies:
Here is a NASA description of LRRK2:
Crystallization of Leucine-rich repeat kinase 2 (LRRK2) under Microgravity Conditions (CASIS PCG 7) will use the orbiting laboratory’s microgravity environment to grow larger versions of this important protein, implicated in Parkinson’s disease. Developed by the Michael J. Fox Foundation, Anatrace and Com-Pac International, researchers will look to take advantage of the station’s microgravity environment which allows protein crystals to grow larger and in more perfect shapes than earth-grown crystals, allowing them to be better analyzed on Earth. Defining the exact shape and morphology of LRRK2 would help scientists to better understand the pathology of Parkinson’s and aid in the development of therapies against this target.
Watch this Michael J. Fox video describing the LRRK2 crystallization experiment:
Video Caption: ISS National Lab SpaceX CRS-12 Payload Overview: Michael J. Fox Foundation. The Michael J. Fox Foundation is sending an experiment to the ISS National Lab to investigate the LRRK2 protein, a key target in identifying the makeup of Parkinson’s disease.
Watch for Ken’s continuing onsite CRS-12, TRDS-M, and ORS 5 and NASA mission reports direct from the Kennedy Space Center and Cape Canaveral Air Force Station, Florida.
Stay tuned here for Ken’s continuing Earth and Planetary science and human spaceflight news.
Learn more about the upcoming SpaceX Dragon CRS-12 resupply launch to ISS on Aug. 14, ULA Atlas TDRS-M NASA comsat on Aug. 18, 2017 Solar Eclipse, NASA missions and more at Ken’s upcoming outreach events at Kennedy Space Center Quality Inn, Titusville, FL:
Aug 12-14: “SpaceX CRS-12 resupply launches to the ISS, Intelsat35e, BulgariaSat 1 and NRO Spysat, SLS, Orion, Commercial crew capsules from Boeing and SpaceX , Heroes and Legends at KSCVC, ULA Atlas/John Glenn Cygnus launch to ISS, SBIRS GEO 3 launch, GOES-R weather satellite launch, OSIRIS-Rex, Juno at Jupiter, InSight Mars lander, SpaceX and Orbital ATK cargo missions to the ISS, ULA Delta 4 Heavy spy satellite, Curiosity and Opportunity explore Mars, Pluto and more,” Kennedy Space Center Quality Inn, Titusville, FL, evenings
Up close view of SpaceX Dragon CRS-11 resupply vessel atop Falcon 9 rocket and delivering 3 tons of science and supplies to the International Space Station (ISS) for NASA. Liftoff occurred 3 June 2017. Credit: Ken Kremer/Kenkremer.comInside the Astrotech payload processing facility in Titusville, FL,NASA’s massive, insect like Tracking and Data Relay Satellite, or TDRS-M, spacecraft is undergoing preflight processing during media visit on 13 July 2017. TDRS-M will transmit critical science data gathered by the ISS, Hubble and numerous NASA Earth science missions. It is being prepared for encapsulation inside its payload fairing prior to being transported to Launch Complex 41 at Cape Canaveral Air Force Station for launch on a United Launch Alliance (ULA) Atlas V rocket on 3 August 2017. Credit: Ken Kremer/kenkremer.com
Artist's concept of a bimodal nuclear rocket making the journey to the Moon, Mars, and other destinations in the Solar System. Credit: NASA
In its pursuit of missions that will take us back to the Moon, to Mars, and beyond, NASA has been exploring a number of next-generation propulsion concepts. Whereas existing concepts have their advantages – chemical rockets have high energy density and ion engines are very fuel-efficient – our hopes for the future hinge on us finding alternatives that combine efficiency and power.
To this end, researchers at NASA’s Marshall Space Flight Center are once again looking to develop nuclear rockets. As part of NASA’s Game Changing Development Program, the Nuclear Thermal Propulsion (NTP) project would see the creation of high-efficiency spacecraft that would be capable of using less fuel to deliver heavy payloads to distant planets, and in a relatively short amount of time.
As Sonny Mitchell, the project of the NTP project at NASA’s Marshall Space Flight Center, said in a recent NASA press statement:
“As we push out into the solar system, nuclear propulsion may offer the only truly viable technology option to extend human reach to the surface of Mars and to worlds beyond. We’re excited to be working on technologies that could open up deep space for human exploration.”
Nuclear reactors (like the one pictured here) are being considered by NASA’s Marshall Space Flight Center for possible future missions. Credit: NASA
To see this through, NASA has entered into a partnership with BWX Technologies (BWXT), a Virginia-based energy and technology company that is a leading supplier of nuclear components and fuel to the U.S. government. To assist NASA in developing the necessary reactors that would support possible future crewed missions to Mars, the company’s subsidiary (BWXT Nuclear Energy, Inc.) was awarded a three-year contract worth $18.8 million.
During this three years in which they will be working with NASA, BWXT will provide the technical and programmatic data needed to implement NTP technology. This will consist of them manufacturing and testing prototype fuel elements and helping NASA to resolve any nuclear licensing and regulatory requirements. BWXT will also aid NASA planners in addressing the issues of feasibility and affordably with their NTP program.
As Rex D. Geveden, BWXT’s President and Chief Executive Officer, said of the agreement:
“BWXT is extremely pleased to be working with NASA on this exciting nuclear space program in support of the Mars mission. We are uniquely qualified to design, develop and manufacture the reactor and fuel for a nuclear-powered spacecraft. This is an opportune time to pivot our capabilities into the space market where we see long-term growth opportunities in nuclear propulsion and nuclear surface power.”
In an NTP rocket, uranium or deuterium reactions are used to heat liquid hydrogen inside a reactor, turning it into ionized hydrogen gas (plasma), which is then channeled through a rocket nozzle to generate thrust. A second possible method, known as Nuclear Electric Propulsion (NEC), involves the same basic reactor converted its heat and energy into electrical energy which then powers an electrical engine.
Artist’s concept of a Bimodal Nuclear Thermal Rocket in Low Earth Orbit. Credit: NASA
In both cases, the rocket relies on nuclear fission to generates propulsion rather than chemical propellants, which has been the mainstay of NASA and all other space agencies to date. Compared to this traditional form of propulsion, both types of nuclear engines offers a number of advantages. The first and most obvious is the virtually unlimited energy density it offers compared to rocket fuel.
This would cut the total amount of propellant needed, thus cutting launch weight and the cost of individual missions. A more powerful nuclear engine would mean reduced trip times. Already, NASA has estimated that an NTP system could make the voyage to Mars to four months instead of six, which would reduce the amount of radiation the astronauts would be exposed to in the course of their journey.
To be fair, the concept of using nuclear rockets to explore the Universe is not new. In fact, NASA has explored the possibility of nuclear propulsion extensively under the Space Nuclear Propulsion Office. In fact, between 1959 and 1972, the SNPO conducted 23 reactor tests at the Nuclear Rocket Development Station at AEC’s Nevada Test Site, in Jackass Flats, Nevada.
In 1963, the SNPO also created the Nuclear Engine for Rocket Vehicle Applications (NERVA) program to develop nuclear-thermal propulsion for long-range crewed mission to the Moon and interplanetary space. This led to the creation of the NRX/XE, a nuclear-thermal engine which the SNPO certified as having met the requirements for a crewed mission to Mars.
Artist’s concept of a bimodal nuclear rocket slowing down to establish orbit around Mars. Credit: NASA
The Soviet Union conducted similar studies during the 1960s, hoping to use them on the upper stages of of their N-1 rocket. Despite these efforts, no nuclear rockets ever entered service, owing to a combination of budget cuts, loss of public interest, and a general winding down of the Space Race after the Apollo program was complete.
But given the current interest in space exploration, and ambitious mission proposed to Mars and beyond, it seems that nuclear rockets may finally see service. One popular idea that is being considered is a multistage rocket that would rely on both a nuclear engine and conventional thrusters – a concept known as a “bimodal spacecraft”. A major proponent of this idea is Dr. Michael G. Houts of the NASA Marshall Space Flight Center.
In 2014, Dr. Houts conducted a presentation outlining how bimodal rockets (and other nuclear concepts) represented “game-changing technologies for space exploration”. As an example, he explained how the Space Launch System (SLS) – a key technology in NASA’s proposed crewed mission to Mars – could be equipped with chemical rocket in the lower stage and a nuclear-thermal engine on the upper stage.
In this setup, the nuclear engine would remain “cold” until the rocket had achieved orbit, at which point the upper stage would be deployed and the reactor would be activated to generate thrust. Other examples cited in the report include long-range satellites that could explore the Outer Solar System and Kuiper Belt and fast, efficient transportation for manned missions throughout the Solar System.
The company’s new contract is expected to run through Sept. 30th, 2019. At that time, the Nuclear Thermal Propulsion project will determine the feasibility of using low-enriched uranium fuel. After that, the project then will spend a year testing and refining its ability to manufacture the necessary fuel elements. If all goes well, we can expect that NASA’s “Journey to Mars” might just incorporate some nuclear engines!
According to a new study by a team of astronomers from the Center of Cosmology at the University of California Irvine, such mergers are far more common than we thought. After conducting a survey of the cosmos intended to calculate and categorize black holes, the UCI team determined that there could be as many as 100 million black holes in the galaxy, a finding which has significant implications for the study of gravitational waves.
The study which details their findings, titled “Counting Black Holes: The Cosmic Stellar Remnant Population and Implications for LIGO“, recently appeared in the Monthly Notices of the Royal Astronomical Society. Led by Oliver D. Elbert, a postdoc student with the department of Physics and Astronomy at UC Irvine, the team conducted an analysis of gravitational wave signals that have been detected by LIGO.
LIGO’s two facilities, located in Livingston, Louisiana, and Hanford, Washington. Credit: ligo.caltech.edu
Their study began roughly a year and a half ago, shortly after LIGO announced the first detection of gravitational waves. These waves were created by the merger of two distant black holes, each of which was equivalent in mass to about 30 Suns. As James Bullock, a professor of physics and astronomy at UC Irvine and a co-author on the paper, explained in a UCI press release:
“Fundamentally, the detection of gravitational waves was a huge deal, as it was a confirmation of a key prediction of Einstein’s general theory of relativity. But then we looked closer at the astrophysics of the actual result, a merger of two 30-solar-mass black holes. That was simply astounding and had us asking, ‘How common are black holes of this size, and how often do they merge?’”
Traditionally, astronomers have been of the opinion that black holes would typically be about the same mass as our Sun. As such, they sought to interpret the multiple gravitational wave detections made by LIGO in terms of what is known about galaxy formation. Beyond this, they also sought to create a framework for predicting future black hole mergers.
From this, they concluded that the Milky Way Galaxy would be home to up to 100 million black holes, 10 millions of which would have an estimated mass of about 30 Solar masses – i.e. similar to those that merged and created the first gravitational waves detected by LIGO in 2016. Meanwhile, dwarf galaxies – like the Draco Dwarf, which orbits at a distance of about 250,000 ly from the center of our galaxy – would host about 100 black holes.
They further determined that today, most low-mass black holes (~10 Solar masses) reside within galaxies of 1 trillion Solar masses (massive galaxies) while massive black holes (~50 Solar masses) reside within galaxies that have about 10 billion Solar masses (i.e. dwarf galaxies). After considering the relationship between galaxy mass and stellar metallicity, they interpreted a galaxy’s black hole count as a function of its stellar mass.
In addition, they also sought to determine how often black holes occur in pairs, how often they merge and how long this would take. Their analysis indicated that only a tiny fraction of black holes would need to be involved in mergers to accommodate what LIGO observed. It also offered predictions that showed how even larger black holes could be merging within the next decade.
As Manoj Kaplinghat, also a UCI professor of physics and astronomy and the second co-author on the study, explained:
“We show that only 0.1 to 1 percent of the black holes formed have to merge to explain what LIGO saw. Of course, the black holes have to get close enough to merge in a reasonable time, which is an open problem… If the current ideas about stellar evolution are right, then our calculations indicate that mergers of even 50-solar-mass black holes will be detected in a few years.”
In other words, our galaxy could be teeming with black holes, and mergers could be happening in a regular basis (relative to cosmological timescales). As such, we can expect that many more gravity wave detections will be possible in the coming years. This should come as no surprise, seeing as how LIGO has made twoadditional detections since the winter of 2016.
With many more expected to come, astronomers will have many opportunities to study black holes mergers, not to mention the physics that drive them!
Artist's impression of the orbits of three of the stars very close to the supermassive black hole at the center of the Milky Way. Credit: ESO/M. Parsa/L. Calçada
At the center of our galaxy, roughly 26,000 light years from Earth, lies the Supermassive Black Hole (SMBH) known as Sagittarius A*. Measuring 44 million km across, this object is roughly 4 million times as massive as our Sun and exerts a tremendous gravitational pull. Since astronomers cannot detect black holes directly, its existence has been determined largely from the effect it has on the small group of stars orbiting it.
In this respect, scientists have found that observing Sagittarius A* is an effective way of testing the physics of gravity. For instance, in the course of observing these stars, a team of German and Czech astronomers noted subtle effects caused by the black hole’s gravity. In so doing, they were able to yet again confirm some of the predictions made by Einstein’s famous Theory of General Relativity.
Artist’s impression of part of S2s orbit around the supermassive black hole at the center of the Milky Way. Credit: ESO/M. Parsa/L. Calçada
From this, they measured the orbits of the stars that orbit Sagittarius A* to test predictions made by classical Newtonian physics (i.e. Universal Gravitation), as well as predictions based on general relativity. What they found was that one of the stars (S2) showed deviations in its orbit which were defied the former, but were consistent with the latter.
This star, which has 15 times the mass of our Sun, follows an elliptical orbit around the SMBH, completing a single orbit in about 15.6 years. At its closest, it gets to within 17 light hours of the black hole, which is the equivalent of 120 times the distance between the Sun and the Earth (120 AU). Essentially, the research team noted that S2 had the most elliptical orbit of any star orbiting the Supermassive Black Hole.
They also noted a slight change in its orbit – a few percent in the shape and about one-sixth of a degree in orientation. This could only be explained as being due to the relativistic effects caused by Sagittarius A* intense gravity, which cause a precession in its orbit. What this means is, the elliptical loop of S2’s orbit rotates around the SMBH over time, with its perihelion point aimed in different directions.
Interestingly enough, this is similar to the effect that was observed in Mercury’s orbit – aka. the “perihelion precession of Mercury” – during the late 19th century. This observation challenged classical Newtonian mechanics and led scientists to conclude that Newton’s theory of gravity was incomplete. It is also what prompted Einstein to develop his theory of General Relativity, which offered a satisfactory explanation for the issue.
Should the results of their study be confirmed, this will be the first time that the effects of general relativity have been precisely calculated using the stars that orbit a Supermassive Black Hole. Marzieh Parsa – a PhD student at the University of Cologne, Germany and lead author of the paper – was understandably excited with these results. As she stated in an ESO press statement:
“The Galactic Center really is the best laboratory to study the motion of stars in a relativistic environment. I was amazed how well we could apply the methods we developed with simulated stars to the high-precision data for the innermost high-velocity stars close to the supermassive black hole.“
This study was made possible thanks to the high-accuracy of the VLT’s instruments; in particular, the adaptive optics on the NACO camera and the SINFONI near-infrared spectrometer. These instruments were vital in tracking the star’s close approach and retreat from the black hole, which allowed for the team to precisely determine the shape of its orbit and thusly determine the relativistic effects on the star.
In addition to the more precise information about S2’s orbit, the team’s analysis also provided new and more accurate estimates of Sagittarius A* mass, as well as its distance from Earth. This could open up new avenues of research for this and other Supermassive Black Holes, as well as additional experiments that could help scientists to learn more about the physics of gravity.
The central parts of our Galaxy, the Milky Way, as observed in the near-infrared with the NACO instrument on ESO’s Very Large Telescope. Credit: ESO/MPE/S. Gillessen et al.
The results also provided a preview of the measurements and tests that will be taking place next year. In 2018, the star S2 will be making a very close approach to Sagittarius A*. Scientists from around the world will be using this opportunity to test the GRAVITY instrument, a second-generation instrument that was recently installed on the Very Large Telescope Interferometer (VLTI).
Developed by an international consortium led by the Max Planck Institute for Extraterrestrial Physics, this instrument has been conducting observations of the Galactic Center since 2016. In 2018, it will be used to measure the orbit of S2 with even greater precision, which is expected to be most revealing. At this time, astrophysicists will be seeking to make additional measurements of the SMBH’s general relativistic effects.
Beyond that, they also hope to detect additional deviations in the star’s orbit that could hint at the existence of new physics! With the right tools trained on the right place, and at the right time, scientists just might find that even Einstein’s theories of gravity were not entirely complete. But in the meantime, it looks like the late and great theoretical physicist was right again!
And be sure to check out this video of the recent study, courtesy of the ESO:
If you are looking forward to the August 21 solar eclipse as much as we are, you’ll want to check out a new series on CuriosityStream called “Eclipse Across America.”
The four-part series takes an inside preview at this highly anticipated event. NASA experts, an international group of astronomers and seasoned eclipse chasers reveal secret viewing spots and tips on how to safely view what could be for millions of people a once-in-a-lifetime opportunity to see one of the most spectacular sights in nature: a total solar eclipse.
Our friend and Astronomy Cast co-host Dr. Pamela Gay, who is also the Director of Technology at the Astronomical Society of the Pacific, is part of the all-star “astronomy cast” (pun intended) of experts, and she talked with us about her part in the show.
“I get to talk about the really cool parts of an eclipse, where you can experience totality and actually feel the temperature change,” she said. Using state-of-the-art special effects, Pamela gets to show off what the eclipse will likely look like at spots around her location in the St. Louis, MO area. “There’s the fickleness of it, where some buildings will see totality and another won’t,” she said. “Of course, the closer you get to the centerline the longer totality will be, and there are some beautiful locations where you can see it.”
A special effects image from CuriosityStream showing how the solar eclipse could look in St. Louis, Missouri. Credit: CuriosityStream.
The really fun part of this particular eclipse is that it takes a path across the entire continental U.S. I asked Pamela if, given the rather divisive political and social climate these days in this country, could this total solar eclipse become a possible unifying moment?
“I think that during the event there will be a lot of overwhelming experiences that people sometimes have of being in a crowd – such as will there be enough bathrooms,” she said. “But afterwards, I think it will be this shared ‘do you remember when’ moment that we’ll have for the rest of our lives. We all have certain moments that we remember and currently here in the US a lot of those memories are ‘where were you when 911 happened? Or where were you when we started bombing Iraq.’ This will be ‘where you when the sun was eclipsed,’ and that is so much better than ‘where were you when the towers fell down.’”
If you already have a CuriosityStream account, you can watch the series starting with Episode One here. If you don’t, you can take advantage of a 7-day free trial in order to watch this series, and all the other great science offerings available, such as Stephen Hawking’s Universe, Brian Cox’s Wonders of Life, and other topics from astronomy observing tips to info about various missions to theoretical physics. Check it out. If you’re interested in continuing after your free trial, the ad-free streaming service costs $2.99, $5.99 and $11.99 per month for standard definition, high definition, and ultra high definition 4K respectively.
The Icarus Pathfinder starship passing by Neptune. Credit: Adrian Mann
Think of the ease. With a simple command of “Make it so” humans travelled from one star to the next in less time than for drinking a cup of coffee. At least that’s what happens in the time-restricted domain of television. In reality it’s not so easy. Nor does Rachel Armstrong misrepresent this point in her book of essays within “Star Ark – A Living Self-Sustaining Spaceship“; a book that brings some fundamental reality to star travel.
Yes, many people want to travel to other stars. We’re not ready for that. We’re still just planning on getting outside Earth’s protective atmosphere (again). Yet making preparations and doing judicious planning is the aim of this book. Wisely though, this book isn’t technical. It has no mention of specific impulse calculations or ion shields. Rather, this book takes a very liberal view of space travel and ponders deep questions such as whether the cosmos is an ecosystem.
Does our species have an appropriate culture for space travel? What exactly is a human? These concerns get raised in some very thought provoking sections. And given that the editor is an architect and one who apparently considers the emotional qualities of a structure as much as functional qualities, then this book’s presentation tends to be a little more on the philosophical side of things.
In particular, it looks at the benefits of living entities. For instance it notes that humans live in symbiotic relationships with a host of internal and external organisms. Most have already gone into space either within people who have traveled in space or possibly upon probes sent to other planets. So we aren’t the only species that’s traveled beyond Earth. But which beings are sufficient and necessary to keep humans alive for the generations needed to travel to another star? That question and many answers come up often.
As well, the essays get into bigger questions such as: What is life? Could the vessel be an organic construct? How might today’s humans evolve to tomorrow’s star travelers? Should humans travel in space and promote/continue panspermia? Yes, these questions and many more are raised in the essays collected within this book. And true to form for any book considering star travel, there aren’t any strict answers. There are however lots of ideas and concepts to better prepare humans.
Much of this book seems to center around the authors’ involvement with the Persephone project of Icarus Interstellar. Yet there’s very little description of either. However, the book does have wonderful descriptions of Biitschli experiments, explanations of living walls and critiques of theatrical productions.
There are a few fictional passages and some poetry. The long list of references indicates a broad knowledge of the technical issues, though the focus is on humanity and the living aspect. This focus flows through the essays, but having a collection of many authors makes for a disjointed flow. The writing styles are unique, the viewpoints are particular and the emphasis specialized for each. One common viewpoint does keep arising though. That is, we are already on a living spaceship; the Earth. Earth gives a unique platform for assessing the ability to travel to other stars. The essays state that it is or at least was a veritable, closed self-sustaining life support system. And, as seems to be the norm these days, the essays acknowledge that solutions for space travel would be just as good for people remaining behind upon Earth or travelling to the Moon or to Mars and so on. This care and concern for living organism keeps the book grounded, so to speak.
The all-encompassing-solution-finder may be a strength or a weakness to Rachel Armstrong’s collection within the book “Star Ark – A Living Self-Sustaining Spaceship”. As the book’s essays describe, humans have an incredible ability to think and act in abstract fashion. Just envisioning an attempt to send sentient beings to another star demonstrates this. But will we be able to enact this idea and what form might a star vessel take? Reading of this is easy. Will taking the necessary steps be just as easy?
