Scientists have been intrigued and puzzled by light-toned layered deposits on Mars since the Mariner spacecraft flybys in the early 1970s. Known as LTDs (Light Toned Deposits), they are Martian sediments that most closely resemble sediments on Earth and are some of the most mysterious features on Mars. Causes for their origin remain unknown, and different mechanisms, including volcanic processes, have been proposed for their formation. But recently data and images from Mars Express suggest that several LTDs were formed when large amounts of groundwater burst on to the surface. Scientists propose that groundwater had a greater role in shaping the Martian surface than previously believed, and may have sheltered primitive life forms as the planet started drying up.
LTDs were some of the first features seen on Mars, because they showed up even in the black and white images sent back by the first spacecraft to flyby Mars. But they are also some of the least understood features on the Red Planet, and have been highly debated. These deposits occur on a large scale in Arabia Terra, Chaotic Terrain and Valles Marineris, close to the Tharsis volcanic bulge.
Now, based on Mars Express data, scientists propose that these sediments are actually younger than originally believed. Angelo Rossi and several colleagues report their findings in a paper published in September of this year in Geophysical Research. They have proposed that several LTDs may have been deposited by large-scale springs of groundwater that burst on to the surface, possibly at different times.
Analysis also indicates that ground water had a more wide-ranging and important role in Martian history than previously believed. Hydrated minerals, relatively young in age, have been found in the region.
Given that the deposits are relatively young in age, and associated with water, they may also have sheltered microbial life from the drier and harsher climate in more recent times on Mars, possibly eliminating the need for a stable atmosphere or a permanent water body.
Direct observation of an exoplanet orbiting the star Fomalhaut - Number 6 in the top 10 (NASA/HST)
[/caption]2008 has been an astounding year of scientific discovery. To celebrate this fact, Time Magazine has listed the “Top 10 Scientific Discoveries” where space exploration and physics dominate. Other disciplines are also listed; including zoology, microbiology, technology and biochemistry, but the number 1 slot goes to the most ambitious physics experiment of our time. Can you guess what it is? Also, of all our endeavours in space, can you pick out three that Time Magazine has singled out as being the most important?
As we approach the end of the year, ready to welcome in 2009, it is good to take stock and celebrate the mind-blowing achievements mankind has accomplished. Read on for the top 10 scientific discoveries of 2008…
The best thing about writing for a leading space news blog is that you gain wonderful overview to all our endeavours in astronomy, space flight, physics, politics (yes, space exploration has everything to do with politics), space commercialization and science in general. 2008 has been such a rich year for space exploration; we’ve landed probes on other worlds, studied other worlds orbiting distant stars, peered deep into the quantum world, learnt profound things about our own planet, developed cutting-edge instrumentation and redefined the human existence in the cosmos. We might not have all the answers (in fact, I think we are only just beginning to scratch the surface of our understanding of the Universe), but we have embarked on an enlightening journey on which we hope to build strong foundations for the next year of scientific discovery.
In an effort to assemble some of the most profound scientific endeavours of this year, Time Magazine has somehow narrowed the focus down to just 10 discoveries. Out of the ten, four are space and physics related, so here they are:
Considering there have never been any direct observations of exoplanets before November 2008–although we have known about the presence of worlds orbiting other stars for many years via indirect methods–this has been a revolutionary year for exoplanet hunters.
4. China Soars into Space: First taikonaut carries out successful spacewalk Zhai Zhigang exits the Shenzhou-7 capsule with Earth overhead (Xinhua/BBC)Following hot on the heels of one of the biggest Olympic Games in Beijing, China launched a three-man crew into space to make history. The taikonauts inside Shenzhou-7 were blasted into space by a Long March II-F rocket on September 25th.
Despite early controversy surrounding recorded spaceship transmissions before the rocket had even launched, and then the sustained efforts by conspiracy theorists to convince the world that the whole thing was staged, mission commander Zhai Zhigang did indeed become the first ever Chinese citizen to carry out a spacewalk. Zhai spent 16 minutes outside of the capsule, attached by an umbilical cable, to triumphantly wave the Chinese flag and retrieve a test sample of solid lubricant attached to the outside of the module. His crew mate Liu Boming was also able to do some spacewalking.
Probably the most incredible thing about the first Chinese spacewalk wasn’t necessarily the spacewalk itself, it was the speed at which China managed to achieve this goal in such a short space of time. The first one-man mission into space was in 2003, the second in 2005, and the third was this year. Getting man into space is no easy task, to build an entire manned program in such a short space of time, from the ground-up, is an outstanding achievement.
2. The North Pole – of Mars: The Phoenix Mars Lander Capturing the world's attention: Phoenix (NASA/UA)Phoenix studied the surface of the Red Planet for five months. It was intended to only last for three. In that time, this robotic explorer captured the hearts and minds of the world; everybody seemed to be talking about the daily trials and tribulations of this highly successful mission. Perhaps it was because of the constant news updates via the University of Arizona website, or the rapid micro-blogging via Twitter; whatever the reason, Phoenix was a short-lived space celebrity.
To give the highly communicative lander the last word, MarsPhoenix on Twitter has recently announced: “Look who made Time Mag’s Top 10 list for Scientific Discoveries in 2008: http://tinyurl.com/5mwt2l”
In the run-up to the switch-on of the LHC in September, the world’s media focused its attention on the grandest physics experiment ever constructed. The LHC will ultimately probe deep into the world of subatomic particles to help to explain some of the fundamental questions of our Universe. Primarily, the LHC has been designed to hunt for the elusive Higgs boson, but the quest will influence many facets of science. From designing an ultra-fast method of data transmission to unfolding the theoretical microscopic dimensions curled up in space-time, the LHC is a diverse science, with applications we won’t fully appreciate for many years.
Unfortunately, as you may be wondering, the LHC hasn’t actually discovered anything yet, but the high-energy collisions of protons and other, larger subatomic particles, will revolutionize physics. I’d argue that the simple fact the multi-billion euro machine has been built is a discovery of how advanced our technological ability is becoming.
Endeavour leaving California at 7am Wednesday morning (NASA)
[/caption]Having flown out of Edwards Air Force Base in California early Wednesday morning, Space Shuttle Endeavour is stopping over at Fort Worth in Texas before making the final leg of its homeward-bound journey to Kennedy Space Center in Florida on Thursday. This is a rare treat for the people of Fort Worth, and anyone who saw the 747/Shuttle duo touch down on the runway Wednesday afternoon will most likely be the last. It is highly unlikely another shuttle will land at Fort Worth ever again…
The weather couldn’t have been more contrasting than the mild California climate. Taking an overnight stay at Forth Worth in Texas before continuing its 747 piggyback ride to Kennedy Space Center tomorrow, Shuttle Endeavour needs to be kept warm through the 30°F freezing night. Plus, the spaceship will be given a VIP heavy guard for the duration.
Endeavour landed at the Fort Worth Joint Reserve Base on Wednesday afternoon after an uneventful taxi ride from Edwards Air Force Base. It had been awaiting the delayed trip home since successful completion of its space station “home improvements” mission (STS-126) on November 30th. Endeavour was originally scheduled for a Sunday commute, but bad weather before Florida caused the extended stay.
So, tonight, the Shuttle has been tucked up warm before making the final leg of the trip (weather permitting). As it is so cold at Fort Worth, engineers have had to make special arrangements to keep the interior of Endeavour warm; whilst on the tarmac they pumped 80°F air into the orbiter. This was to preserve delicate seals and expensive equipment inside.
Although this mammoth taxi ride isn’t cheap (every time NASA performs this cross-country hop, it costs the agency approximately $1.8 million), the 747 pilots seem to enjoy the change in plans for the Shuttle landing site. “When they do occasionally land at Edwards, we always say ‘Shucks, they had to land at Edwards,” joked Frank Marlow, NASA 747 Pilot.
Since 1981, NASA has sent a 747 to the west coast 52 times to pick up the shuttle fleet. The last time a Space Shuttle landed at Fort Worth was in 1997. Alas, this will probably be the final time North Texas will see another shuttle before the fleet is decommissioned in 2010.
Here’s your image for this week’s “Where In The Universe” challenge. Take a look and see if you can name where in the Universe this image is from, and also guess what exactly this image is — there are a few different features here — just what are they? Give yourself extra points if you can name the spacecraft responsible for the image. The image will be posted today, but we won’t reveal the answer until tomorrow. Post your guess in the comment section, and then check back tomorrow and see how you did. Good luck!
UPDATE (12/12): The answer has now been posted below. If you haven’t made your guess yet, no peeking before you do!!
Thanks for being more discreet in adding your guesses in the comment section (no one put any links this time!) The readers don’t have to name their sources! Thanks for playing, and I hope you’ll play again next week!
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Grab your 3-D glasses and prepare to be amazed (and addicted!) The team from the remarkable HiRISE Camera on board the Mars Reconnaissance Orbiter has released a collection of 3-D images — 362 of ’em — of Mars surface. The incredible power of this camera can resolve features as small as one meter, or 40 inches, across, and in looking at these 3-D images, it’s almost like being there. Above is one of my favorites from this collection, Arabia Terra. “It’s really remarkable to see Martian rocks and features on the scale of a person in 3-D,” said Alfred McEwen of UA’s Lunar and Planetary Laboratory, HiRISE principal investigator. “The level of detail is just much, much greater than anything previously seen from orbit.”
How was the team able to create so many 3-D images? And how can you get or make a pair of 3-D glasses?
Usually, creating 3-D anaglyphs is a tedious and time-consuming process. But the HiRISE team was able to automate some of the software used in processing the images so two images of a stereo pair could be fed into the software “pipeline” and correlated automatically. So look for even more 3-D images in the future. But 362 should keep most of us busy, for awhile anyway!
Here, spectacular layers are exposed on the floor of a large canyon in the Valles Marineris system called Candor Chasma which is about 2-and-a-half miles, or 4 kilometers deep. The canyon may once have been filled to its rim by sedimentary layers of sand and dust-sized particles, but these have since eroded, leaving patterns of elongated hills and layered terrain that has been turned and folded in many angles and directions.
If you don’t have a pair of 3-D glasses, here’s a link to a list of several sources of finding some, or you can even make your own. Sometimes, 3-D glasses can be found for free on cereal boxes, or in children’s books or other sources.
Becquerel Crater. Credit: NASA/JPL/UA
Here is a 3-D version of Becquerel Crater, and the layered terrain of which we wrote about last week, which was formed by cyclical climate change.
Saturn, Venus and Mercury. Image credit: Jimmy Westlake
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Venus and Mercury are the two planets that orbit closest to the Sun. Mercury orbits at an average distance of 58 million km, while Venus orbits at a distance of 108 million km. Mercury takes 88 Earth days to complete an orbit, and Venus takes 225 days to orbit the Earth.
And as you’d probably guess, Venus and Mercury are the two hottest planets in the Solar System, but not in the order that you’d think. Even though Mercury orbits closer to the Sun than Venus, it lacks an atmosphere. The side facing the Sun is baked, with a temperature of 425 degrees Celsius, the side facing away from the Sun cools down to -193 degrees Celsius. Venus, on the other hand, has an incredibly thick atmosphere and traps the heat from the Sun. No matter where you go on the planet, the temperature on the surface of Venus is always 462 degrees Celsius.
The composition of Venus and Mercury is similar, they’re both terrestrial planets made of rock and metal. Mercury is more dense than Venus and thought to consist of 60-70% metal, with the rest rock. As mentioned above, Mercury lacks an atmosphere, while Venus has the thickest atmosphere of all the terrestrial planets. The temperatures and pressures are so extreme on the surface of Venus that spacecraft only last a few hours before being crushed and baked.
Both Venus and Mercury are within the orbit of Earth. This means that they’re always located near the Sun in the sky. Sometimes they rise before the Sun, and then fade away as the Sun rises, and sometimes they’re set after the Sun. They appear as the sky darkens, and then pass below the horizon within a few minutes. You need to have a clear view to the horizon to see Mercury, and know when to go looking. Venus, on the other hand can appear quite high in the sky, and is very bright. In fact, Venus is the brightest object in the sky after the Moon.
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Ancient people have known about the planets since we were able to look up. Some stars were brighter than the rest, and seemed to move across the sky from night to night. These moving stars were known as planets, and there were 5: Mercury, Venus, Mars, Jupiter and Saturn. But the movements of the planets were puzzling to ancient astronomers. Some times the planets would slow down, go backwards, and then go forwards again. When a planet goes backwards, it’s called retrograde, and one of the best planets for this is Mercury. Let’s examine Mercury retrograde.
In ancient times, people thought the Earth was the center of the Universe, and all objects in the night sky orbited around us. One complication of this model was the planets which took these very predictable retrograde paths in their orbit. If the planets were orbiting the Earth, why would they go backwards? Why would Mercury go retrograde? They developed elaborate models where the planets followed a spiraling path around the Earth to account for this retrograde motion.
It wasn’t until Nicolaus Copernicus developed his Sun-centered model of the Solar System that the bizarre retrograde motion of Mercury and the rest of the planets finally made sense. The Earth is just another planet, and they’re all orbiting the Sun together. The retrograde motion of Mercury and the other planets is due to our relative positions in orbit.
So let’s understand retrograde motion, and look at what is Mercury retro in particular. The motion of the planets around the Sun follow the right-hand rule. Hold your right hand out, make a fist and stick the thumb up. The direction of the thumb points in the direction of the Sun’s northern pole. The curve of the fingers indicates the direction all the planets orbit around the Sun.
Mercury moves faster than the Earth as it travels around the Sun; however, Mercury has a highly elliptical orbit, so the speed of its orbit changes. When Mercury is furthest from the Sun, it’s at the slowest point in its orbit, and this gives the Earth a chance to “catch up”. Imagine you’re driving next to a car in the freeway which is speeding up and slowing down. It’s still going down the highway at a high speed, but it seems to be going back and forth compared to you. When this happens, astronomers say that Mercury is in retrograde.
Astrologers seem to think that retrograde motion is an unlucky or bad situation because it goes against a planet’s natural movements. Of course, the planet isn’t really changing its motions at all, it’s only our perspective of the planet that’s changing. Furthermore, at any one time, 40% of the outer planets are in retrograde motion anyway. Something’s almost always in retrograde.
Is Mercury in retrograde right now? It depends on the date. Check the list of dates below to check.
So when is Mercury going to be in retrograde? Here are some Mercury retrograde dates for the next few years.
Endeavour successfully took off atop a 747 this morning under blue skies. Farewell Endeavour, it was a joy to have you visit (NASA)
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Update:Space Shuttle Endeavour left Edwards Air Force Base this morning at 7am, after a 10-day stop over in the Mojave Desert, 65 miles northeast of Los Angeles. Have a safe flight to Florida Endeavour, it was great to have you as a guest!
You’ve probably heard this announcement at the airport before: “Flight delayed due to bad weather.” Quickly followed by, “You can’t be serious!” from the red-faced guy behind you, slamming his briefcase to the floor, resulting in an angry hoard of commuters rushing to the ticket desk to blame the airline for the snow storm outside (because the natural phenomenon of snow is their fault).
However, at Edwards Air Force Base in California, another, more patient passenger awaits her flight back to Florida. But rather than the delay being a matter of minutes or hours, Space Shuttle Endeavour’s flight to Florida has been delayed by three days, and counting…
Endeavour had an astounding mission (STS-126) to the International Space Station last month. The shuttle carried a team of seven to perform one of the busiest 16-day orbital stop-overs yet. The crew completed several spacewalks to fix stiff solar alpha rotary joints, upgraded the station modules to accommodate six permanent station crew members and transported some cool educational experiments into space.
"I just heard some sort of explosion!" Nope, it was just that pesky space shuttle... (LA Times)All in all, STS-126 was an outright success. Even the confused spiders in the biology experiment payload performed with excellence, dealing with microgravity and spinning a web just like they did on Earth. Everything appeared to go pretty much without incident (apart from the loss of a $100,000 toolbag), that was until Endeavour was told to land 2000 miles off target due to bad weather over Florida. Rather than returning to home soil, the shuttle landed at Edwards Air Force Base in the Mojave Desert in California (buzzing the locals on November 30th).
So alternative arrangements had to be made to ferry the shuttle back to Kennedy Space Center, and this included a customized NASA Boeing 747 jumbo jet taxi ride (with a fare of $1.8 million). Endeavour will enjoy a piggyback ride atop the aircraft, hopefully taking off first thing in the morning (Wednesday).
NASA is keeping a close eye on the weather front causing the problems; Endeavour was tentatively scheduled to fly home on Sunday, but poor weather between California and Florida pushed the delay further into the week. NASA does not allow the flying duo to pass through cloud or any inclement weather, so they are allowed to be picky about when to fly.
The stars in the centre of our galaxy. Our supermassive black hole IS in there, somewhere... (ESO)
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One the one hand, this might not be surprising news, but on the other, the implications are startling. A supermassive black hole (called Sagittarius A*) lives at the centre of the Milky Way. This is the conclusion of a 16 year observation campaign of a region right in the centre of our galaxy where 28 stars have been tracked, orbiting a common, invisible point.
Usually these stars would be obscured by the gas and dust in that region, but the European Southern Observatory (ESO) in Chile has used its infrared telescopes to peer deep into the black hole’s lair. Judging by the orbital trajectories of these 28 stars, astronomers have not only been able to pinpoint the black hole’s location, they have also deduced its mass…
It has been long recognised that supermassive black holes probably occupy the centres of most galaxies, from dwarf galaxies to thin galactic disks to large spiral galaxies; the majority of galaxies appear to have them. But actually seeing a black hole is no easy task; astronomers depend on observing the effect a supermassive black hole has on the surrounding gas, dust and stars rather than seeing the object itself (after all, by definition, a black hole is black).
In 1992, astronomers using the ESO’s 3.5-metre New Technology Telescope in Chile turned their attentions on our very own galactic core to begin an unprecedented observation campaign. Since 2002, the 8.2-metre Very Large Telescope (VLT) was also put to use. 16 years later, with over 50 nights of total observation time, the results are in.
By tracking individual stars orbiting a common point, ESO researchers have derived the best empirical evidence yet for the existence of a 4 million solar mass black hole. All the stars are moving rapidly, one star even completed a full orbit within those 16 years, allowing astronomers to indirectly study the mysterious beast driving our galaxy.
“The centre of the Galaxy is a unique laboratory where we can study the fundamental processes of strong gravity, stellar dynamics and star formation that are of great relevance to all other galactic nuclei, with a level of detail that will never be possible beyond our Galaxy,” explains Reinhard Genzel, team leader of this research at the Max-Planck-Institute for Extraterrestrial Physics in Garching near Munich, Germany.
“Undoubtedly the most spectacular aspect of our 16-year study, is that it has delivered what is now considered to be the best empirical evidence that super-massive black holes do really exist,” Genzel continues. “The stellar orbits in the galactic centre show that the central mass concentration of four million solar masses must be a black hole, beyond any reasonable doubt.”
Apart from being the most detailed study of Sagittarius A*’s neighbourhood (the techniques used in this study are six-times more precise than any study before it), the ESO astronomers also deduced the most precise measurement of the distance from the galactic centre to the Solar System; our supermassive black hole lies a safe 27,000 light years away.
A lot of information was gleaned about the individual stars too. “The stars in the innermost region are in random orbits, like a swarm of bees,” says Stefan Gillessen, first author of the paper published in The Astrophysical Journal. “However, further out, six of the 28 stars orbit the black hole in a disc. In this respect the new study has also confirmed explicitly earlier work in which the disc had been found, but only in a statistical sense. Ordered motion outside the central light-month, randomly oriented orbits inside – that’s how the dynamics of the young stars in the Galactic Centre are best described.”
Quite simply, the object influencing these stars must be a supermassive black hole, there is no other explanation out there. Does this mean black holes have an even firmer standing as a cosmological “fact” rather than “theory”? It would appear so…
How hot is it on Mercury? Color image of Mercury. Image credit: NASA
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Mercurian world is one of extremes. 700 Kelvin on the side exposed to the Sun, yet some areas are never exposed to sunlight and are as cold as deep space. Scientists do not believe there has ever been life on Mercury. The atmosphere on Mercury is almost non-existant. It doesn’t protect the planet from the harsh radiation of the Sun or radiation from space, nor does it trap heat and provide a breathable atmosphere. Mercury is inhospitable and sterile.
In order for life (as we know it) to exist, Mercury would need to have temperatures that allow liquid water to remain on its surface for long periods of time. But the temperatures on Mercury extend from just above absolute zero when the surface is shadowed to 700 Kelvin when its in sunlight. Liquid water just can’t exist in that kind of environment.
Any ancient life on Mercury would have faced many extinction events. Here on Earth many past life forms have been destroyed by asteroid impacts. The dinosaurs are a classic example. Images of Mercury’s surface returned by the Mariner 10 and MESSENGER spacecraft have shown that the surface has suffered many large impacts. In fact, it was heavily bombarded during the Late Heavy Bombardment that occurred about 3.9 billion years ago. Any one of those impacts could have destroyed any life on the planet. Many scientists believe that a great deal of the planet’s surface was stripped away by one impact. If the impact removed a large portion of the surface, surely it would have taken any life that existed at the time with it.
All evidence that science has do date indicates that there has never been life on Mercury and never will be. The harsh conditions on the planet’s surface and the tenuous atmosphere make it impossible for any life form known to man to exist.
But there are other planets in the Solar System. Here’s an article about life on Pluto, and here’s one about life on Mars.
