An artist's conception of future Mars astronauts. Credit: NASA/JPL-Caltech
While asking questions about habitability on Mars, one thing that scientists also need to consider is whether it’s safe enough for humans to even do exploration there. Radiation is definitely a big factor — in a press conference yesterday (Dec. 9) for the American Geophysical Union’s conference, scientists said the environment is unlike anything we are used to naturally on Earth.
Radiation on Mars comes from two sources: galactic cosmic rays (over the long term) and solar energetic particles (in short bursts of activity when the sun gets super-active). Of note, the sun has had a muted peak to its solar cycle, so that’s affecting the expected amount of particles on Mars. But the Mars Curiosity rover, in its first 300 Earth days of roaming, has plenty of data on galactic cosmic rays.
On the Martian surface, the average dose is about 0.67 millisieverts (mSv) per day, at least between the measurement period of August 2012 and June 2013. The journey to Mars had a dose of 1.8 mSv per day inside the spaceship. So what does that means for NASA’s human health consideration concerns?
NASA’s Mars rover Curiosity took this self-portrait, composed of more than 50 images using its robotic arm-mounted MAHLI camera, on Feb. 3. The image shows Curiosity at the John Klein drill site. A drill hole is visible at bottom left. Credit: NASA / JPL / MSSS / Marco Di Lorenzo / Ken Kremer- kenkremer.com
With a 500-day trip on the surface and the journey to and from Mars (which would take 180 days each way), NASA is saying the total dosage for the mission would be about 1 Sv. Population studies over the long term have shown that increases the fatal cancer risk by 5%. Current NASA guidelines for low-Earth orbit don’t allow for a more than 3% increase, but 1 Sv is within the guidelines for several other space agencies.
But don’t rule out the trip to Mars yet, NASA states: “[NASA] does not currently have a limit for deep space missions, and is working with the National Academies Institute of Medicine to determine appropriate limits for deep space missions, such as a mission to Mars in the 2030s.”
Besides, other entities are thinking about going, such as Mars One.
Read more about the radiation findings in this Dec. 9 article on Science. The research was led by Don Hassler, a Southwest Research Institute program director and principal investigator of Curiosity’s radiation assessment detector (RAD).
Molecular hydrogen in the Whirlpool Galaxy M51. The blueish features show the distribution of hydrogen molecules in M51, the raw material for forming new stars. The PAWS team has used this data to create a catalogue of more then 1,500 molecular clouds. The background is a color image of M51 by the Hubble Space Telescope. Superimposed in blue is the CO(1-0) radiation emitted by carbon monoxide (CO) molecules, as measured for the PAWS study using the millimeter telescopes of the Institut de Radioastronomie Millimétrique. The CO molecules are used as tracers for molecular hydrogen. Credit: PAWS team/IRAM/NASA HST/T. A. Rector (University of Alaska Anchorage)
It didn’t happen overnight. By studying the properties of giant molecular clouds in the Whirlpool Galaxy for several years with the millimeter telescopes of IRAM, the Institut de Radioastronomie Millimétrique, astronomers have been given a whole, new look at star formation. Encompassing 1,500 maps of molecular clouds, this new research has found these building blocks of future suns to be encased in a sort of molecular hydrogen mist. This ethereal mixture appears to be far denser than speculated and is found throughout the galactic disc. What’s more, it would appear the pressure created by the molecular fog is a critical factor in determining whether or not stars are able to form within the clouds.
Stars form in the molecular clouds housed within all galaxies. These formations are vast areas of hydrogen molecules with masses which total from a thousand to several million times that of the Sun. When an area of the cloud folds under the weight of its own gravity, it collapses. Pressure and temperature rise and nuclear fusion begins. A star is born.
This exciting new research is changing the way astronomers think about starbirth regions. Study leader Eva Schinnerer (Max Planck Institute for Astronomy) explains: “Over the past four years, we have created the most complete map yet of giant molecular clouds in another spiral galaxy similar to our own Milky Way, reconstructing the amounts of hydrogen molecules and correlating them with the presence of new or older stars. The picture that is emerging is quite different from what astronomers thought these clouds should be like.” The survey, known as PAWS, targeted the Whirlpool galaxy, also known as M51, at a distance of about 23 million light-years in the constellation Canes Venatici – the Hunting Dogs.
Annie Hughes, a post-doctoral researcher at MPIA involved in the study, says: “We used to think of giant molecular clouds as solitary objects, drifting within the surrounding interstellar medium of rarified gas in isolated splendor; the main repository of a galaxy’s supply of hydrogen molecules. But our study shows that 50% of the hydrogen is outside the clouds, in a diffuse, disk-shaped hydrogen fog permeating the galaxy!”
Not only does the enveloping gas play a critical part in star formation, but galaxy structure does as well. One galactic feature in particular is key – spiral arm structure. They sweep slowly around the core area like hands on a clock and are more populated with stars than the remainder of the galactic disk. Sharon Meidt, another MPIA post-doctoral researcher involved in the study, says: “These clouds are definitely not isolated. On the contrary, interactions between clouds, fog, and overall galactic structure appear to hold the key to whether or not a cloud will form new stars. When the molecular fog moves relative to the galaxy’s spiral arms, the pressure it exerts on any clouds within is reduced, in line with a physical law known as Bernoulli’s principle. Clouds feeling this reduced pressure are unlikely to form new stars. According to the press release, Bernoulli’s law is also thought to be responsible for part of the well-known shower-curtain effect: shower curtains blowing inward when one takes a hot shower, another display of reduced pressure.
Jerome Pety of the Institut de Radioastronomie Millimétrique (IRAM), which operates the telescopes used for the new observations, says: “It’s good to see our telescopes live up to their full potential. A study that needed such extensive observation time, and required both an interferometer to discern vital details and our 30 m antenna to put those details into a larger context, would not have been possible at any other observatory.”
Schinnerer concludes: “So far, the Whirlpool galaxy is one example which we have studied in depth. Next, we need to check that what we have found also applies to other galaxies. For our next steps, we hope to profit from both the extension NOEMA of the compound telescope on the Plateau de Bure and from the newly opened compound telescope ALMA in Chile, which will allow in-depth studies of more distant spiral galaxies.”
Outcrops in Yellowknife Bay are being exposed by wind driven erosion. These rocks record superimposed ancient lake and stream deposits that offered past environmental conditions favorable for microbial life. This image mosaic from the Mast Camera instrument on NASA's Curiosity Mars rover shows a series of sedimentary deposits in the Glenelg area of Gale Crater, from a perspective in Yellowknife Bay looking toward west-northwest. The "Cumberland" rock that the rover drilled for a sample of the Sheepbed mudstone deposit (at lower left in this scene) has been exposed at the surface for only about 80 million years. Credit: NASA/JPL-Caltech/MSSS
NASA’s Curiosity rover has discovered evidence that an ancient Martian lake had the right chemical ingredients that could have sustained microbial life forms for long periods of time – and that these habitable conditions persisted on the Red Planet until a more recent epoch than previously thought.
Furthermore researchers have developed a novel technique allowing Curiosity to accurately date Martian rocks for the first time ever – rather than having to rely on educated guesses based on counting craters.
All that and more stems from science results just announced by members of the rover science team.
Researchers outlined their remarkable findings in a series of six new scientific papers published today (Dec. 9) in the highly respected journal Science and at talks held today at the Fall 2013 Annual Meeting of the American Geophysical Union (AGU) in San Francisco.
The Curiosity team also revealed that an investigation of natural Martian erosion processes could be used to direct the rover to spots with a higher likelihood of holding preserved evidence for the building blocks of past life – if it ever existed.
View of Yellowknife Bay Formation, with Drilling Sites
This mosaic of images from Curiosity’s Mast Camera (Mastcam) shows geological members of the Yellowknife Bay formation, and the sites where Curiosity drilled into the lowest-lying member, called Sheepbed, at targets “John Klein” and “Cumberland.” The scene has the Sheepbed mudstone in the foreground and rises up through Gillespie Lake member to the Point Lake outcrop. These rocks record superimposed ancient lake and stream deposits that offered past environmental conditions favorable for microbial life. Rocks here were exposed about 70 million years ago by removal of overlying layers due to erosion by the wind. Credit: NASA/JPL-Caltech/MSSS
The ancient fresh water lake at the Yellowknife Bay area inside the Gale Crater landing site explored earlier this year by Curiosity existed for periods spanning perhaps millions to tens of millions of years in length – before eventually evaporating completely after Mars lost its thick atmosphere.
Furthermore the lake may have existed until as recently as 3.7 Billion years ago, much later than researchers expected which means that life had a longer and better chance of gaining a foothold on the Red Planet before it was transformed into its current cold, arid state.
NASA’s Mars rover Curiosity took this self-portrait, composed of more than 50 images using its robotic arm-mounted MAHLI camera, on Feb. 3. The image shows Curiosity at the John Klein drill site. A drill hole is visible at bottom left. Credit: NASA / JPL / MSSS / Marco Di Lorenzo / Ken Kremer- kenkremer.com
Researchers also announced that they are shifting the missions focus from searching for habitable environments to searching for organic molecules – the building blocks of all life as we know it.
Why the shift? Because the team believes they have found a way to increase the chance of finding organics preserved in the sedimentary rock layers.
“Really what we’re doing is turning the corner from a mission that is dedicated to the search for habitable environments to a mission that is now dedicated to the search for that subset of habitable environments which also preserves organic carbon,” Curiosity Principal Investigator John Grotzinger, of the California Institute of Technology in Pasadena, said at an AGU press conference today.
“That’s the step we need to take as we explore for evidence of life on Mars.”
Earlier this year, Curiosity drilled into a pair of sedimentary Martian mudstone rock outcrops at Yellowknife Bay known as “John Klein” and “Cumberland” – for the first time in history.
Grotzinger said the ancient lake at Yellowknife Bay was likely about 30 miles long and 3 miles wide.
Powdered samples deposited into the rovers miniaturized chemistry labs – SAM and CheMin – revealed the presence of significant levels of phyllosilicate clay minerals.
These clay minerals form in neutral pH water that is ‘drinkable” and conducive to the formation of life.
“Curiosity discovered that the fine-grained sedimentary rocks preserve evidence of an environment that would have been suited to support a Martian biosphere founded on chemolithoautotrophy,” according to one of the science papers co-authored by Grotzinger.
“This aqueous environment was characterized by neutral pH, low salinity, and variable redox states of both iron and sulfur species.”
The rover has detected key elements required for life including carbon, hydrogen, oxygen, sulfur nitrogen and phosphorous.
The team is still looking for signatures of organic molecules.
Right now the researchers are driving Curiosity along a 6 mile path to the base of Mount Sharp -the primary mission destination – which they hope to reach sometime in Spring 2014.
But along the way they hope to stop at a spot where wind has eroded the sedimentary rocks just recently enough to expose an area that may still preserve evidence for organic molecules – since it hasn’t been bombarded by destructive cosmic radiation for billions of years.
Stay tuned here for Ken’s continuing Curiosity, Chang’e 3, LADEE, MAVEN and MOM news.
Dec 11: “Curiosity, MAVEN and the Search for Life on Mars”, “LADEE & Antares ISS Launches from Virginia”, Rittenhouse Astronomical Society, Franklin Institute, Phila, PA, 8 PM
With remote-sensing satellites, scientists have found the coldest places on Earth, just off a ridge in the East Antarctic Plateau. The coldest of the cold temperatures dropped to minus 135.8 F (minus 93.2 C) -- several degrees colder than the previous record.
Image Credit: Ted Scambos, National Snow and Ice Data Center.
What is the coldest place on Earth? Scientists say it’s a place so cold that ordinary mercury or alcohol thermometers won’t work there. If you were there, every breath would be painful, your clothing would crackle every time you moved, and if you threw hot water into the air, it would fall to the ground as tiny shards of ice. At this place, the new record of minus 136 F (minus 93.2 C) was set on Aug. 10, 2010. Researchers analyzed data from several satellite instruments and found the coldest place on Earth in the past 32 years is … a high ridge in Antarctica between Dome Argus and Dome Fuji, two summits on the ice sheet known as the East Antarctic Plateau. Temperatures in several hollows were found to dip to the new record.
“We had a suspicion this Antarctic ridge was likely to be extremely cold,” said Ted Scambos, from the National Snow and Ice Data Center in Boulder, Colorado. “With the launch of Landsat 8, we finally had a sensor capable of really investigating this area in more detail.”
This beats out the previous low of minus 128.6 F (minus 89.2 C), set in 1983 at the Russian Vostok Research Station in East Antarctica. The coldest permanently inhabited place on Earth is northeastern Siberia, where temperatures in the towns of Verkhoyansk and Oimekon dropped to a bone-chilling 90 degrees below zero Fahrenheit (minus 67.8 C) in 1892 and 1933, respectively.
Scambos and his team made the discovery while analyzing the most detailed global surface temperature maps to date, developed with data from remote sensing satellites. The new findings were reported at the American Geophysical Union meeting in San Francisco.
The pursuit to find the coldest place on Earth started when the researchers were studying large snow dunes, sculpted and polished by the wind, on the East Antarctic Plateau. When the scientists looked closer, they noticed cracks in the snow surface between the dunes, possibly created when wintertime temperatures got so low the top snow layer shrunk. This led scientists to wonder what the temperature range was, and prompted them to hunt for the coldest places using data from two types of satellite sensors.
They used data from the Moderate Resolution Imaging Spectroradiometer (MODIS) instruments on NASA’s Terra and Aqua satellites and the Advanced Very High Resolution Radiometer (AVHRR) on several National Oceanic and Atmospheric Administration satellites. These sensitive instruments can pick up thermal radiation emitted from Earth’s surface, even in areas lacking much heat.
Using these sensors to scan the East Antarctic Plateau, Scambos detected extremely cold temperatures on a 620-mile stretch of the ridge at high elevations between Argus and Fuji, and even colder temperatures lower elevations in pockets off the ridge. Then, with the higher resolution of the Thermal Infrared Sensor (TIRS) aboard Landsat 8, the research team pinpointed the record-setting pockets.
The team compared the sites to topographic maps to explore how it gets so cold. Already cold temperatures fall rapidly when the sky clears. If clear skies persist for a few days, the ground chills as it radiates its remaining heat into space. This creates a layer of super-chilled air above the surface of the snow and ice. This layer of air is denser than the relatively warmer air above it, which causes it to slide down the shallow slope of domes on the Antarctic plateau. As it flows into the pockets, it can be trapped, and the cooling continues.
“By causing the air to be stationary for extended periods, while continuing to radiate more heat away into space, you get the absolute lowest temperatures we’re able to find,” Scambos said. “We suspected that we would be looking for one magical site that got extremely cold, but what we found was a large strip of Antarctica at high altitude that regularly reached these record low temperatures.”
The Moon, via the Scientific Visualization Studio.
Here’s how the Moon will look to us on Earth during the entire year of 2014. Using data from the Lunar Reconnaissance Orbiter, the Goddard Space Flight Center Scientific Visualization Studio can project how the Moon will appear, and compresses one month into 24 seconds and a year to about 5 minutes. Above is the video where Celestial north is up, corresponding to the view from the northern hemisphere, and below is how the Moon will look from the southern hemisphere.
While the Moon always keeps the same face to us, it’s not exactly the same face. Because of the tilt in its axis and shape of its orbit, we see the Moon from slightly different angles over the course of a month, and the year. Normally, we don’t see how the Moon “wobbles” in its orbit, but seeing the Moon’s year this quickly, we can see the changes in libration, and axis tilt — as well as the most noticeable changes, the Moon’s phases.
Find out more at this SVS page, where you can also “Dial a Moon” — put in a specific date and see how the Moon will look on that day.
Universe Today also has a great app for your iPhone or Android that can also show you how the Moon will look any day in the past or present.
The morning zodiacal as seen from near Rodeo, New Mexico, looking east at 5:00 am December 6, 2013. Credit and copyright: Alan Dyer/Amazing Sky Photography.
Sometimes, if you are lucky, dawn comes before the dawn. The zodiacal light – or false dawn, as it is sometimes called – is an ethereal light extending up from the horizon, sometimes seen about an hour before sunrise or an hour after sunset. At one time, it was thought this was an atmospheric phenomenon, but it’s more cosmic than that! Zodiacal light is sunlight reflecting off dust grains in space. These dust grains are likely left over from the same process that created Earth and the other planets of our solar system 4.5 billion years ago.
Alan Dyer captured this beautiful view of the zodiacal light on a recent trip to New Mexico. If you look closely you can see some other cosmic phenomena as well: “Mars is above centre and Saturn is just rising over the mountain ridge,” Alan wrote on Flickr. “Comet Lovejoy C/2013 R1 is at far left. The image includes the position (left of centre, above the mountains left of the Zodiacal Light) where Comet ISON (C/2012 S2) would have been had it survived passage around the Sun.”
Want to get your astrophoto featured on Universe Today? Join our Flickr group or send us your images by email (this means you’re giving us permission to post them). Please explain what’s in the picture, when you took it, the equipment you used, etc.
The Universe is filled with hot fusion, in the cores of stars. And scientists have even been able to replicate this stellar process in expensive experiments. But wouldn’t it be amazing if you could produce energy from fusion without all that equipment, and high temperatures and pressures? Pons and Fleischmann announced exactly that back in 1989, but things didn’t quite turn out as planned…
Here is another giveaway just in time for the holidays: The Constellation Observing Atlas by Grant Privett and Kevin Jones. Springer and Universe Today are giving away free copies to two lucky Universe Today readers.
Review by: Evan Gough
The night sky is vast and full of wonders, and binoculars or a telescope can bring these wonders into view. The planets and the moon are easy to find, but after that, the rest of the objects in the night sky can be challenging to locate. “The Constellation Observing Atlas,” by Grant Privett and Kevin Jones, will guide you around the night sky, and help you find the most interesting objects.
This atlas uses the patterns of the constellations to cut the sky up into bite-sized pieces, giving the amateur observer an easy to use method for exploring the night sky. “The Constellation Observing Atlas” has a section for each one of the eighty-eight constellations recognized by the International Astronomical Union, from Andromeda to Vulpecula.
General information about each constellation is included, followed by the history of its name and mapping, any notable double and variable stars are mentioned and any deep sky objects that reside in or near the constellation are listed. Along with some nice images, “The Constellation Observing Atlas” also has detailed maps of each constellation which helps make the observing process straightforward.
The book is well laid out, and the amount of information for each constellation is just right. The maps are detailed and helpful and I found the history sections very interesting and amusing. The authors don’t mind having a little fun at the ancient’s expense for some of their comical constellation choices and the convoluted myths behind them, and who can blame them? Many of the constellations are just vague clumps and arrangements of stars in which the ancients somehow saw their most powerful gods, mythical creatures, and heroes.
Like many Universe Today readers, I’m interested in all things astronomy and space, but I’m far from an expert observer. “The Constellation Observing Atlas” tries to make the night sky accessible for amateurs like myself, and it works. You simply locate a constellation in the sky, check the book for interesting viewing targets, point your ‘scope around, and have some fun. Some of the stars and deep sky objects will be challenging to find, and the authors give detailed information for finding these elusive targets.
In my part of the world, winter has come and I’m in store for some clear, cold, crisp nights. There should be some great observing conditions ahead, with Orion prominent in the night sky. I’m looking forward to using “The Constellation Observing Atlas” to expand my observing. The authors have done a good job of being informative and fun, and I highly recommend this book to amateur and novice observers. It makes the wonders of the night sky accessible, one constellation at a time.
In order to be entered into the giveaway drawing, just put your email address into the box at the bottom of this post (where it says “Enter the Giveaway”) before Monday, December 16th, 2013. We’ll send you a confirmation email, so you’ll need to click that to be entered into the drawing.
Don’t want to wait to see if you won? Get your copy in time for Christmas from Amazon.com
An image from ESA's Mars Express taken in May of 2010 shows the north pole of Mars during the red planet's summer solstice. All the carbon dioxide ice has gone, leaving just a bright cap of water ice. Credit: ESA.
Get a satellite’s-eye view of the Martian north pole in this new animation from the Mars Express spacecraft, using data from the Mars Advanced Radar for Subsurface and Ionospheric Sounding instrument, MARSIS. This instrument allows for studying the surface heights, providing a 3-D view of the Mars’ north pole.
You can see the prominent gap in the ice cap, which is a 318 km-long, 2 km-deep chasm called Chasma Boreale.
In all, the ice cap has a diameter of about 1000 km and consists of many thin layers of ice mixed with dust that extend to a depth of around 2 km below the cap.
ESA says the layers result from variations in the orbit and rotation of Mars that affect the amount of sunlight received at the poles, and thus the amount of melting and deposition of materials over time. Meanwhile, strong prevailing winds are thought to be responsible for shaping the spiral troughs.
The MARSIS instrument works by sending low-frequency radio waves towards the surface of Mars, and they are reflected back to the spacecraft from the planet’s surface. The strength and timing of the radar echoes are a gauge of the depths of different types of interfaces, such as between rock, water or ice.
Video credit: ESA/ASI/NASA/JPL/La Sapienza University/INAF (A. Frigeri)
Composite image of Circinus X-1, which is about 24,000 light-years from Earth in the constellation Circinus. Credit: X-ray: NASA/CXC/Univ. of Wisconsin-Madison/S. Heinz et al; Optical: DSS; Radio: CSIRO/ATNF/ATCA
Circinus X-1 may look like a serene place from a distance, but in reality this gassy nebula is quite a busy spot. Embedded in the nebula is the neutron star that is also a leftover of the supernova that produced the gas. Not only that, but the neutron star is still locked on to a companion and is in fact “cannibalizing” it, astronomers said.
The “glowing wreck of a star”, as the team called it, is exciting because it demonstrates what systems look like in the first stages after an explosion. The nebula is an infant in cosmic terms, with an upper limit to its age of just 4,500 years. To put that in human terms, that’s around the time of the first civilizations (such as in Mesopotamia).
“The fact that we have this remnant along with the neutron star and its companion means we can test all kinds of things,” stated Sebastian Heinz, an astronomy professor at the University of Wisconsin-Madison who led the research.
“Our observations solve a number of puzzles both about this object and the way that neutron stars evolve after they are born. For example, the unusual elliptical orbit on which these two stars swing around each other is exactly what you would expect for a very young X-ray binary.”
X-ray binaries are typically made up of a black hole or a neutron star that is locked on to a “normal” companion star such as that of our sun. That star won’t stay normal forever, however, as it’s being subject to very intense gravity from the black hole or neutron star. Its starstuff is being pulled off, heated, and then emitting radiation in X-rays that are easily trackable across the universe.
While X-ray binaries have been spotted before, seeing one along with a nebula is something special. By comparison, the gas cloud doesn’t stick around for very long — just 100,000 years or so — while the stars can be there for a while longer.
Checking out this star system could not only teach scientists about stellar evolution, but about the nature of neutron stars. One thing puzzling the team right now is why the neutron star has a faint magnetic field, which stands against established theory. Further study will be required to figure out why it isn’t as strong as expected.
A binary X-ray system with a black hole (right) and companion star. Credit: ESO/L. Calçada
This high-resolution view from NASA’s Chandra X-Ray Telescope and the Australia Telescope Compact Array, however, has revealed some new things.
“I have been perplexed by the unusually strong evolution of the orbit of Circinus X-1 since my graduate-school days,” stated Niel Brandt, an astronomer at Pennsylvania State University who is on the team. “The discovery now of this system’s youth provides a satisfying explanation for why its orbit evolves so strongly — because the system likely still is settling down after its violent birth.”
You can read more in the Dec. 4 publication in The Astrophysical Journal or, in prepublished form, on Arxiv.
