An oblique view from the Lunar Reconnaissance Orbiter of Icarus Crater on the Moon. The shadow created by the unusual central peak in the crater is reminiscent of a certain Star Wars character. Icarus is approximately 94 km in diameter. Credit: NASA/GSFC/Arizona State University.
Scientists from the Lunar Reconnaissance Orbiter say that Icarus Crater is one of a kind on the Moon because its central peak rises higher than about half its rim. Most central peaks rise only about halfway to the crater rim. But at just the ring angle and lighting conditions, the shadow this central peak creates on the rolling and jagged crater rim looks like the Star Wars Character Yoda. Interestingly, this crater is located on what some people erroneously call the “Dark Side” of the Moon – what is actually the lunar farside.
Yoda meditates about moons. Via Blastr.com
Below you can see a closeup of the central peak of Icarus crater rising out of the shadows to greet a new lunar day.
The central peak of Icarus Crater on the Moon’s farside, as seen by LROC. Image width is approximately 10 km, north is to the right. Credit: NASA/GSFC/Arizona State University.
Icarus is located just west of Korolev crater on the lunar farside. The light-colored plains surrounding the craters were deposited during the formation of the Orientale basin, which is located over 1500 km away.
Image from LRO’s Wide Angle Camera of Icarus crater and vicinity. Image width is approximately 365 km. Credit: NASA/GSFC/Arizona State University.
Find out more about these images from LRO and see larger versions at the LROC website.
The speeding rogue star Kappa Cassiopeiae sets up a glowing bow shock in this Spitzer image (NASA/JPL-Caltech)
That might seem like a sensational headline worthy of a supermarket tabloid but, taken in context, it’s exactly what’s happening here!
The bright blue star at the center of this image is a B-type supergiant named Kappa Cassiopeiae, 4,000 light-years away. As stars in our galaxy go it’s pretty big — over 57 million kilometers wide, about 41 times the radius of the Sun. But its size isn’t what makes K Cas stand out — it’s the infrared-bright bow shock it’s creating as it speeds past its stellar neighbors at a breakneck 1,100 kilometers per second.
K Cas is what’s called a runway star. It’s traveling very fast in relation to the stars around it, possibly due to the supernova explosion of a previous nearby stellar neighbor or companion, or perhaps kicked into high gear during a close encounter with a massive object like a black hole.
As it speeds through the galaxy it creates a curved bow shock in front of it, like water rising up in front of the bow of a ship. This is the ionized glow of interstellar material compressed and heated by K Cas’ stellar wind. Although it looks like it surrounds the star pretty closely in the image above, the glowing shockwave is actually about 4 light-years out from K Cas… slightly less than the distance from the Sun to Proxima Centauri.
The bow shock of Zeta Ophiuchi, another runaway star observed by Spitzer (NASA/JPL-Caltech)
Although K Cas is visible to the naked eye, its bow shock isn’t. It’s only made apparent in infrared wavelengths, which NASA’s Spitzer Space Telescope is specifically designed to detect. Some other runaway stars have brighter bow shocks — like Zeta Ophiuchi at right — which can be seen in optical wavelengths (as long as they’re not obscured by dust, which Zeta Oph is.)
The bright wisps seen crossing K Cas’ bow shock may be magnetic filaments that run throughout the galaxy, made visible through interaction with the ionized gas. In fact bow shocks are of particular interest to astronomers precisely because they help reveal otherwise invisible features and allow deeper investigation into the chemical composition of stars and the regions of the galaxy they are traveling through. Like a speeding car on a dark country road, runaway stars’ bow shocks are — to scientists — like high-beam headlamps lighting up the space ahead.
Runaway stars are not to be confused with rogue stars, which, although also feel the need for speed, have been flung completely out of their home galaxies.
Curiosity looks back eastward to ‘Dingo Gap’ sand dune inside Gale Crater. After crossing over the 3 foot (1 meter) tall dune on Sol 539, Feb. 9, 2014 the rover drove westward into the ‘Moonlight Valley’. The parallel rover wheel tracks are 9 feet (2.7 meters) apart. Assembled from Sol 539 colorized navcam raw images. Credit: NASA/JPL/ Ken Kremer- kenkremer.com/Marco Di Lorenzo
Curiosity looks back eastward to ‘Dingo Gap’ sand dune inside Gale Crater
After crossing over the 3 foot (1 meter) tall dune on Sol 539, Feb. 9, 2014 the rover drove westward into the ‘Moonlight Valley’. The parallel rover wheel tracks are 9 feet (2.7 meters) apart. Assembled from Sol 539 colorized navcam raw images. Credit: NASA/JPL/ Ken Kremer- kenkremer.com/Marco Di Lorenzo
See Dune and Wheel mosaics below – Story updated [/caption]
The team directing the epic trek of NASA’s Curiosity rover across the floor of Gale Crater has adopted new driving strategies and a new way forward in response to the unexpected wheel damage caused by driving over fields of rough edged Red Planet rocks in recent months.
This week, engineers directed dune buggy Curiosity to drive backwards for a lengthy distance over the Martian surface for the first time since landing.
The SUV sized vehicle apparently passed the reverse driving feasibility test with flying colors and is now well on the way to the exciting journey ahead aiming for the sedimentary layers at the base of towering Mount Sharp – the primary mission destination – which reaches 3.4 miles (5.5 km) into the Martian sky and possesses water altered minerals.
“We wanted to have backwards driving in our validated toolkit because there will be parts of our route that will be more challenging,” said Curiosity Project Manager Jim Erickson of NASA’s Jet Propulsion Laboratory, Pasadena, Calif, in a statement.
On Tuesday, Feb. 18, Curiosity not only drove in reverse, but the 329 feet (100.3 meters) distance covered marked her farthest one-day advance in over three months.
And she is also now roving over the much sought after smoother Martian terrain, as hoped, when the team decided to alter the traverse route based on high resolution imaging observations collected by the telescopic camera on NASA’s Mars Reconnaissance Orbiter (MRO) circling overhead.
The goal is to minimize wear and tear on the 20 inch diameter wheels.
This map shows the route driven and route planned for NASA’s Curiosity Mars rover from before reaching “Dingo Gap” — in upper right — to the mission’s next science waypoint, “Kimberley” (formerly referred to as “KMS-9”) — in lower left. Credit: NASA/JPL-Caltech/Univ. of Arizona
Engineers were forced to devise new driving techniques and consider a new route forward after the aluminum wheels accumulated significant punctures and rips during the past few months of driving over fields strewn with sharp edged Martian rocks.
“We have changed our focus to look at the big picture for getting to the slopes of Mount Sharp, assessing different potential routes and different entry points to the destination area,” Erickson said.
“No route will be perfect; we need to figure out the best of the imperfect ones.”
But to reach the smooth terrain and the science rich targets located on the pathway ahead, the six wheeled rover first had to pass through a gateway known as the ‘Dingo Gap’ sand dune.
Curiosity’s View Past Tall Dune at edge of ‘Dingo Gap’
This photomosaic from Curiosity’s Navigation Camera (Navcam) taken at the edge of the entrance to the Dingo Gap shows a 3 foot (1 meter) tall dune and valley terrain beyond to the west, all dramatically back dropped by eroded rim of Gale Crater. View from the rover’s current position on Sol 528 (Jan. 30, 2014). The rover team may decide soon whether Curiosity will bridge the dune gap as a smoother path to next science destination. Credit: NASA/JPL-Caltech/Marco Di Lorenzo/Ken Kremer- kenkremer.com
“Moonlight Valley” is the name of the breathtaking new locale beyond Dingo, Curiosity Principal Investigator John Grotzinger, of Caltech, told Universe Today.
Curiosity crossed through the 3 foot (1 meter) tall Dingo Gap sand dune with ease on Feb. 9 and roved on to targets in the “Moonlight Valley” and the region beyond.
“Moonlight Valley has got lots of veins cutting through it,” Grotzinger told me.
“We’re seeing recessive bedrock.”
Curiosity scans Moonlight Valley beyond Dingo Gap Dune. Curiosity’s view to “Moonlight Valley” beyond after crossing over ‘Dingo Gap’ sand dune. This photomosaic was taken after Curiosity drove over the 1 meter tall Dingo Gap sand dune and shows dramatic scenery in the valley beyond, back dropped by eroded rim of Gale Crater. Assembled from navigation camera (navcam) raw images from Sol 535 (Feb. 6, 2104) Credit: NASA/JPL-Caltech/Ken Kremer- kenkremer.com/Marco Di Lorenzo
Since passing through the Dingo Gap gateway, Curiosity has traveled another 937 feet (285.5 meters) for a total mission odometry of 3.24 miles (5.21 kilometers) since the nail biting landing on Aug. 6, 2012.
“After we got over the dune, we began driving in terrain that looks like what we expected based on the orbital data. There are fewer sharp rocks, many of them are loose, and in most places there’s a little bit of sand cushioning the vehicle,” Erickson said.
Curiosity looks back to ‘Dingo Gap’ sand dune after crossing over, backdropped by Mount Sharp on Sol 540, Feb. 12, 2014. Rear hazcam fisheye image linearized and colorized. Credit: NASA/JPL/Marco Di Lorenzo/Ken Kremer- kenkremer.com
Curiosity’s near term goal is to reach her next science waypoint, named Kimberly (formerly called KMS-9) which lies about two-thirds of a mile (about 1.1 kilometers) ahead.
Kimberly is of interest to the science team because it sits at an the intersection of different rock layers.
The 1 ton robot may be directed to drill into another rock at Kimberly.
If approved, Kimberly would be her first since drilling operation since boring into Cumberland rock target last spring and since departing the Yellowknife Bay region in July 2013 where she discovered a habitable zone.
Curiosity looks back to ‘Dingo Gap’ sand dune after crossing over, backdropped by Mount Sharp on Sol 535, Feb. 5, 2014. Hazcam fisheye image linearized and colorized. Credit: NASA/JPL/Marco Di Lorenzo/Ken Kremer- kenkremer
To date Curiosity’s odometer stands at 5.2 kilometers and she has taken over 118,000 images. The robot has about another 5 km to go to reach the foothills of Mount Sharp.
Stay tuned here for Ken’s continuing Curiosity, Opportunity, Chang’e-3, SpaceX, Orbital Sciences, LADEE, MAVEN, MOM, Mars and more planetary and human spaceflight news.
Up close photomosaic view shows lengthy tear in rover Curiosity’s left front wheel caused by recent driving over sharp edged Martian rocks on the months long trek to Mount Sharp. Raw images taken by the MAHLI camera on Curiosity’s arm on Jan. 31, 2014 (Sol 529) were assembled to show some recent damage to several of its six wheels Credit: NASA / JPL / MSSS / Marco Di Lorenzo / Ken Kremer- kenkremer.com
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An exoplanet transiting across the face of its star, demonstrating one of the methods used to find planets beyond our solar system. Credit: ESA/C. Carreau
With exoplanet discoveries coming at us several times a month, finding these worlds is a hot field of research. Once the planets are found and confirmed, however, there’s a lot more that has to be done to understand them. What are they made of? How habitable are they? What are their atmospheres like? These are questions we are only beginning to understand.
One long-standing exoplanet researcher argues that we don’t know very much about about alien planet atmospheres, as an example. Princeton University’s Adam Burrows says that not only is our understanding at an infancy, but the media and scientists overhype information based on very little data.
“Exoplanet research is in a period of productive fermentation that implies we’re doing something new that will indeed mature,” Burrows stated in a story posted on Princeton Journal Watch. “Our observations just aren’t yet of a quality that is good enough to draw the conclusions we want to draw.”
Artist’s conception of HD 189733 b, which may have winds that blow up to 22,000 mph (35,000 km/h). Credit: NASA
Burrow’s skepticism comes from how information on exoplanet atmospheres is collected. That uses a method called low-resolution photometry, which shows changes in light and radiation emitted from an object such as a planet. This could be affected by things such as a planet’s rotation and cloud cover.
Burrows’ solution is to use spectrometry, which can glean physical information through looking at light spectra, but that would be a challenge given the existing exoplanet-seeking infrastructure in space and on Earth uses telescopes that generally rely on other methods.
NASA’s Galileo spacecraft arrived at Jupiter on December 7, 1995, and proceeded to study the giant planet for almost 8 years. It sent back a tremendous amount of scientific information that revolutionized our understanding of the Jovian system. By the end of its mission, Galileo was worn down. Instruments were failing and scientists were worried they wouldn’t be able to communicate with the spacecraft in the future. If they lost contact, Galileo would continue to orbit the Jupiter and potentially crash into one of its icy moons.
Galileo would certainly have Earth bacteria on board, which might contaminate the pristine environments of the Jovian moons, and so NASA decided it would be best to crash Galileo into Jupiter, removing the risk entirely. Although everyone in the scientific community were certain this was the safe and wise thing to do, there were a small group of people concerned that crashing Galileo into Jupiter, with its Plutonium thermal reactor, might cause a cascade reaction that would ignite Jupiter into a second star in the Solar System.
Hydrogen bombs are ignited by detonating plutonium, and Jupiter’s got a lot of hydrogen.Since we don’t have a second star, you’ll be glad to know this didn’t happen. Could it have happened? Could it ever happen? The answer, of course, is a series of nos. No, it couldn’t have happened. There’s no way it could ever happen… or is there?
Jupiter is mostly made of hydrogen, in order to turn it into a giant fireball you’d need oxygen to burn it. Water tells us what the recipe is. There are two atoms of hydrogen to one atom of oxygen. If you can get the two elements together in those quantities, you get water.
In other words, if you could surround Jupiter with half again more Jupiter’s worth of oxygen, you’d get a Jupiter plus a half sized fireball. It would turn into water and release energy. But that much oxygen isn’t handy, and even though it’s a giant ball of fire, that’s still not a star anyway. In fact, stars aren’t “burning” at all, at least, not in the combustion sense.
Jupiter as imaged by Michael Phillips on July 25th, 2009.
Our Sun produces its energy through fusion. The vast gravity compresses hydrogen down to the point that high pressure and temperatures cram hydrogen atoms into helium. This is a fusion reaction. It generates excess energy, and so the Sun is bright. And the only way you can get a reaction like this is when you bring together a massive amount of hydrogen. In fact… you’d need a star’s worth of hydrogen. Jupiter is a thousand times less massive than the Sun. One thousand times less massive. In other words, if you crashed 1000 Jupiters together, then we’d have a second actual Sun in our Solar System.
But the Sun isn’t the smallest possible star you can have. In fact, if you have about 7.5% the mass of the Sun’s worth of hydrogen collected together, you’ll get a red dwarf star. So the smallest red dwarf star is still about 80 times the mass of Jupiter. You know the drill, find 79 more Jupiters, crash them into Jupiter, and we’d have a second star in the Solar System.
There’s another object that’s less massive than a red dwarf, but it’s still sort of star like: a brown dwarf. This is an object which isn’t massive enough to ignite in true fusion, but it’s still massive enough that deuterium, a variant of hydrogen, will fuse. You can get a brown dwarf with only 13 times the mass of Jupiter. Now that’s not so hard, right? Find 13 more Jupiters, crash them into the planet?
As was demonstrated with Galileo, igniting Jupiter or its hydrogen is not a simple matter.
We won’t get a second star unless there’s a series of catastrophic collisions in the Solar System.
And if that happens… we’ll have other problems on our hands.
Artist's impression of an asteroid breaking up. Credit: NASA/JPL-Caltech
When you throw a bunch of rock and debris at a rapidly spinning star, what happens? A new study suggests that so-called pulsar stars change their dizzying spin rate as asteroids fall into the gaseous mass. This conclusion comes from observations of one pulsar (PSR J0738-4042) that is being “pounded” with debris from rocks, researchers said.
Lying 37,000 light-years from our planet in the southern constellation Puppis, this supernova remnant’s environment is swarming with rocks, radiation and “winds of particles”. One of those rocks likely was more than a billion metric tonnes in mass, which is nowhere near the mass of Earth (5.9 sextillion tonnes), but is still substantial.
“If a large rocky object can form here, planets could form around any star. That’s exciting,” stated Ryan Shannon, a researcher with the Commonwealth Scientific and Industrial Research Organisation who participated in the study.
Pulsars are sometimes called the clocks of the universe because their spins, fast as they are, precisely emit radio beams with each revolution — a beam that can be seen from Earth if our planet and the star are aligned in the right way. A 2008 study by Shannon and others predicted the spin could be altered by debris falling into the pulsar, which this new research appears to confirm.
Artist’s conception of stellar rubble around pulsar 4U 0142+61. Credit: NASA/JPL-Caltech
“We think the pulsar’s radio beam zaps the asteroid, vaporizing it. But the vaporized particles are electrically charged and they slightly alter the process that creates the pulsar’s beam,” Shannon said.
As stars explode, the researchers further suggest that not only do they leave behind a pulsar star remnant, but they also throw out debris that could then fall back towards the pulsar and create a debris disc. Another pulsar, J0146+61, appears to display this kind of disc. As with other protoplanetary systems, it’s possible the small bits of matter could gradually clump together to form bigger rocks.
You can read the study in Astrophysical Journal Letters or in preprint version on Arxiv. The study was led by Paul Brook, a Ph.D. student co-supervised by the University of Oxford and CSIRO. Observations were performed with the Hartebeesthoek Radio Astronomy Observatory in South Africa, and CSIRO’s Parkes radio telescope.
Artist's conception of exoplanet systems that could be observed by PLAnetary Transits and Oscillations of stars (PLATO), a European Space Agency telescope. Credit: ESA - C. Carreau
How could life arise in young solar systems? We’re still not sure of the answer on Earth, even for something as basic as if water arose natively on our planet or was carried in from other locations. Seeking answers to life’s beginnings will require eyes in the sky and on the ground looking for alien worlds like our own. And just yesterday, the European Space Agency announced it is going to add to that search.
The newly selected mission is called PLATO, for Planetary Transits and Oscillations. Like NASA’s Kepler space telescope, PLATO will scan the sky in search of stars that have small, periodic dips in their brightness that happen when planets go across their parent star’s face.
“The mission will address two key themes of Cosmic Vision: what are the conditions for planet formation and the emergence of life, and how does the solar system work,” stated ESA, referring to its plan for space science missions that extends from 2015 to 2025.
An exoplanet seen from its moon (artist’s impression). Via the IAU.
PLATO will operate far from Earth in a spot known as L2, a relatively stable Lagrange point about 1.5 million kilometers (930,000 miles) away from Earth in the opposite direction from the sun. Sitting there for at least six years, the observatory (which is actually made up of 34 small telescopes and cameras) will examine up to a million stars across half of the sky.
Find “statistically significant” Earth-mass planets in the habitable regions of several kinds of main-sequence stars;
Figure out the radius and mass of the star and any planets with 1% accuracy, and estimate the age of exoplanet systems with 10% accuracy;
Better determine the parameters of different kinds of planets, ranging from brown dwarfs (failed stars) to gas giants to rocky planets, all the way down to those that are smaller than Earth.
Artist’s impression of the deep blue planet HD 189733b, based on observations from the Hubble Space Telescope. Credit: NASA/ESA.
Adding PLATO’s observations to those telescopes on the ground that look at the radial velocity of planets, researchers will also be able to figure out each planet’s mass and radius (which then leads to density calculations, showing if it is made of rock, gas, or something else).
“The mission will identify and study thousands of exoplanetary systems, with an emphasis on discovering and characterising Earth-sized planets and super-Earths in the habitable zone of their parent star – the distance from the star where liquid surface water could exist,” ESA stated this week.
The telescope was selected from four competing proposals, which were EChO (the Exoplanet CHaracterisation Observatory), LOFT (the Large Observatory For x-ray Timing), MarcoPolo-R (to collect and return a sample from a near-Earth asteroid) and STE-Quest (Space-Time Explorer and QUantum Equivalence principle Space Test).
You can read more about PLATO at this website. It’s expected to launch from Kourou, French Guiana on a Soyuz rocket in 2024, with a budget of 600 million Euros ($822 million). And here’s more information on the Cosmic Vision and the two other M-class missions launching in future years, Euclid and Solar Orbiter.
A team of astronomers from South Africa have noticed a series of supermassive black holes in distant galaxies that are all spinning in the same direction. Credit: NASA/JPL-Caltech
Gas around supermassive black holes tends to clump into immense clouds, periodically blocking the view of these huge X-ray sources from Earth, new research reveals.
Observations of 55 of these “galactic nuclei” revealed at least a dozen times when an X-ray source dimmed for a time as short as a few hours or as long as years, which likely happened when a gas cloud blotted out the signal seen from Earth. This is different than some previous models suggesting the gas was more uniform.
“Evidence for the clouds comes from records collected over 16 years by NASA’s Rossi X-ray Timing Explorer, a satellite in low-earth orbit equipped with instruments that measured variations in X-ray sources,” stated the Royal Astronomical Society.
“Those sources include active galactic nuclei, brilliantly luminous objects powered by supermassive black holes as they gather and condense huge quantities of dust and gas.”
The research was led by Alex Markowitz, an astrophysicist at the University of California, San Diego and the Karl Remeis Observatory in Bamberg, Germany.
