Posted on by Nancy Atkinson

Snow on Mercury?

No, not that kind of snow, but scientists say deep inside the planet Mercury, iron “snow” forms and falls toward the center of the planet, much like snowflakes form in Earth’s atmosphere and fall to the ground. The movement of this iron snow could be responsible for Mercury’s mysterious magnetic field, and Mercury may be the only body in our solar system where this occurs.

Mercury and Earth are the only local terrestrial planets that possess a global magnetic field. But Mercury’s is about 100 times weaker than Earth’s, which scientists have been unable to explain.

Made mostly of iron, Mercury’s core is also thought to contain sulfur, which lowers the melting point of iron and plays an important role in producing the planet’s magnetic field.

To better understand the physical state of Mercury’s core, the researchers in a lab recreated the conditions believed to exist at Mercury’s core, and melted an iron-sulfur mixture at high pressures and high temperatures.

In each experiment, an iron-sulfur sample was compressed to a specific pressure and heated to a specific temperature. The sample was then quenched, cut in two, and analyzed with a scanning electron microscope and an electron probe microanalyzer.

As the molten, iron-sulfur mixture in the outer core slowly cools, iron atoms condense into cubic “flakes” that fall toward the planet’s center, said Bin Chen, University of Illinois graduate student and lead author of a paper published in the April issue of Geophysical Research Letters. As the iron snow sinks and the lighter, sulfur-rich liquid rises, convection currents are created that power the dynamo and produce the planet’s weak magnetic field.

The researchers say their findings provide a new context for the data that will be obtained from NASA’s MESSENGER spacecraft, which will flyby Mercury for a second time on October 6, 2008. It will pass by the planet again in September of 2009, and go into orbit in March of 2011.

Original News Source: Eureka Alert

Here are some interesting facts about Mercury.

Posted on by Nancy Atkinson

Where In The Universe? #4

Here’s this week’s “Where In The Universe?” mystery image. Your mission, should you choose to accept, is to guess what location in the universe is depicted here. No peeking below before you make a guess. Give yourself an extra point if you can name the feature shown here, and another point or two if you can name the spacecraft that took this image. I have to admit, I was drawn to this image strictly by the color: blue is my favorite, and especially this shade of blue. Kind of electric, don’t you think? Let’s see, could this be a moon, or a planet, or even a portion of a planetary nebula, or perhaps a photo from somewhere on our home planet? Make your guesses now, or maybe you knew what this was the moment you saw it….

Have you made your guess?

This spectacular image was taken by the Hubble Space Telescope. It’s a close-up view of an electric-blue aurora that is eerily glowing on the planet Jupiter. It was taken by HST’s Space Telescope Imaging Spectrograph (STIS) using an ultraviolet filter.

Auroras are curtains of light resulting from high-energy electrons racing along the planet’s magnetic field into the upper atmosphere. The electrons excite atmospheric gases, causing them to glow. The aurora is centered on Jupiter’s magnetic north pole.

Although this aurora resembles the same phenomenon seen at Earth’s polar regions, this image shows unique emissions from the magnetic “footprints” of three of Jupiter’s largest moons. These points are reached by following Jupiter’s magnetic field from each satellite down to the planet.

Auroral footprints can be seen in this image from Io (along the left hand limb), Ganymede (near the center), and Europa (just below and to the right of Ganymede’s auroral footprint). These emissions, produced by electric currents generated by the satellites, flow along Jupiter’s magnetic field, bouncing in and out of the upper atmosphere. They are unlike anything seen on Earth.

This ultraviolet image of Jupiter was taken with the on November 26, 1998. In this ultraviolet view, the aurora stands out clearly, but Jupiter’s cloud structure is masked by haze.

So, how’d you do?

Image credit: NASA/ESA, John Clarke (University of Michigan)

Link to image on the Hubble Site.

Posted on by Nancy Atkinson

JAXA Releases Boomerang Experiment Video

During the STS-123 mission to the International Space Station in March 2008 Japanese astronaut Takeo Doi tested a special boomerang in space to see how it worked in the microgravity environment of the ISS. The boomerang used in the experiment was a “Roomerang,” a small, tri-blade boomerang intended for use indoors in a small area or outdoors in light winds. IT was designed by boomerang expert Gary Broadbent, and it travels 5 to 8 feet before returning to the thrower.

The Japanese Space Agency has now released the video of the event:

As you can see, it worked very well, even in the small space of the ISS module. Broadbent told Universe Today that in the pressurized environment of the ISS, “microgravity has very little effect on the boomerang flight. The boomerang is so versatile, it can be tuned to fly in a perfect path back to the thrower, with gyroscopic precession and angular momentum over-compensating the lack of gravity.”

But Broadbent also said that a boomerang would not work in the vacuum of space. “You need air molecules to generate the lift to make the boomerang turn,” he said.

Here’s our earlier article about the boomerang experiment.

Original News Source: You Tube

Posted on by Ian O'Neill

NASA Considers Manned Asteroid Mission

Low gravity on an asteroid would be a big issue (NASA)

What would happen if we spot a Near-Earth Asteroid (NEO) heading straight for us? Assuming we had enough time, we might be able to pull together a group of brave astronauts (or oil drillers) and send them to the asteroid just in the nick of time to destroy it… oh hold on, that sounds like the storyline for a Hollywood blockbuster. Actually, NASA is planning a mission to an NEO, but not because it’s aimed at us. An asteroid named 2000SG344 (which threatened the Earth in the year 2000) is being considered as the destination for the first manned asteroid mission. The asteroid astronauts will travel there, chasing the 28,000 mi/hr (45,000 km/hr) speeding body and then carry out experiments, living on it for up to two weeks. Why? To briefly establish a manned outpost, advancing science and technology toward the ultimate goal: Mars.

The 1.1 million tonne asteroid was once thought to be a serious threat Earth. Back in 2000, there was a significant chance that asteroid 2000SG344 may have been on a collision course for Earth (with an explosive power of approximately 1 megatonne). Obviously it wasn’t, but it is expected to make an astronomically close flyby in 2030. Before then, NASA hopes to use this 40 meter-wide asteroid as the destination of a three to six month manned mission.

The asteroid mission would act as a “stepping stone” for future planetary missions to Mars and beyond. This three-month trek would provide vital technological, psychological and practical clues to what a manned deep space mission would face. Landing on an asteroid will be very difficult (due to the tiny influence of gravity on such a low-mass body), but it would provide an opportunity for astronauts to mine for water ice, use it for consumption and convert it into its component hydrogen and oxygen (for fuel and breathing). These tests would be essential before sending man on a long-term mission to Mars.

Under the current US administration, NASA has been instructed to send man back to the Moon by 2020. It is hoped that a more permanent base will be established soon after. Once the Moon base has been established, missions to Mars will become much easier to carry out. However, manned trips to near-Earth asteroids allow us to learn more about this potentially catastrophic hazard as well as developing deep space technology for the human presence on Mars.

In a study to be published in June, scientists at NASA’s Johnson Space Centre in Houston and Ames Research Centre in California will provide a rundown of their plans to use the future Orion spacecraft for this task, with a stop over of one- or two-weeks. I’m looking forward to seeing their recommendations for this ambitious development…

Source: The Guardian (UK)

Posted on by Ian O'Neill

Will Mars Astronauts be put in Suspended Animation for the Journey?

Sigourney Weaver in the film Alien (Brandywine Productions Ltd.)

Could you handle six months in space with a tiny handful of crew? Keep in mind you’d be doing everything with them, eating, sleeping, chatting, working, waiting, more sleeping, the occasional emergency, more chatting… If you look around your office now, could you really see yourself spending 24/7 with any of those guys for 24 weeks? Even the happiest, close-knit family would find it hard, especially at the close quarters they are likely to endure. Even if you had to spend that time with your partner, someone you love dearly, there would be stresses… after all you can’t exactly storm out of the spaceship and float home. You’re in it for the long-term.

The solution? Put the astronauts on their way to Mars into a suspended animation state. This not only saves the astronauts from potentially dangerous arguments, it would also save on food, air and water. So how can this be done? Hydrogen sulfide, the gas produced by rotten eggs, may be able to help…

Peggy Whitson, NASA astronaut, spent a record breaking six months on board the International Space Station (she returned on April 19th with a bit of a bump) and it appears she was able to make it through the days on board the ISS with her crew. However, the ISS had a very busy few months, plus it’s had several changes of crew and various new modules have been added. The ISS is a very different environment to work in than on board future missions to Mars. For starters, the main mission is to get to the Red Planet; the transit from Earth will be seen as the “run-up”. Although valuable science will undoubtedly be done, the accommodations are likely to be cramped and Mars astronauts will see the same faces day in and day out. Confrontations could become a serious problem. Supplying the ship with enough food and water for the trip will also be a difficult task. How can all these issues be faced? Put the astronauts in suspended animation.

Probably more familiar in science fiction movies (like the 1979 classic Alien, pictured top), suspended animation has some serious problems. Cooling the human body was thought to be the key to slowing the metabolism down sufficiently so space-bound crews could slip into hibernation for the duration of the long trip, but it seems this interferes with the rhythm of the heart. Now scientists at Harvard believe they have a solution.

Dr Warren Zapol, the head of anaesthesiology at Harvard University’s Massachusetts General Hospital, has been working on the effects that hydrogen sulfide has on the human body. More commonly known for the pungent smell produced by rotten eggs, hydrogen sulphide has been used on mice and the results have been very interesting. When breathed in, the gas slows mouse metabolism, but does not reduce the flow of blood to the brain and doesn’t interfere with the heart.

“The mice aren’t asleep. If you pinch their tails they respond. I don’t know what it’s like. Probably some slow-motion world.” – Dr Warren Zapol.

After about ten minutes of inhaling the gas, the mice slipped into a hibernation state. A reduction in oxygen consumption and carbon dioxide production was measured. This reduction continued for as long as hydrogen sulfide was administered and the test subjects recovered fully after normal air flow was supplied for 30 minutes. What’s more, oxygen levels in the blood did not vary, signifying that the major organs were not at risk of being oxygen starved. Mouse heart rate also dropped by 50%.

Of course many tests will be needed before hydrogen sulfide is administered to humans, let alone astronauts, but the preliminary results are encouraging. It looks like mice are joining the monkeys in mankind’s future on Mars…

Source:
ABC Science

Posted on by Nancy Atkinson

Did Earth Have More Than One Moon?

Scientists looking at the various Lagrangian Points in our solar system noticed a pattern. Lagrange points, (named after their discoverer Josef Lagrange) are five special locations in the vicinity of two orbiting masses where a third, smaller mass can orbit at a fixed distance from the larger masses. Essentially, the gravity from each large mass is equal at that point and the smaller object can be “trapped” there. The 4th and 5th Largrange points, called L4 and L5, are stable points. Researchers Jack Lissauera, and John Chambers noticed that more than 2200 cataloged asteroids are located about the L4 and L5 points of the Sun–Jupiter system, and five bodies have been discovered around the L4 point of the Sun–Neptune system. Small satellites have also been found librating about the L4 and L5 points of two of Saturn’s moons. However, no objects have been discovered around the Earth–Moon L4 and L5 points. Their research led them to believe that other small moons may once have existed in these points.

The triangular Lagrange points, L4 and L5, form equilateral triangles with the two massive bodies (here, the Earth and the moon) and objects near L4 and L5 can remain close to these locations indefinitely.

Lissauera and Chambers say that using numerical integrations, they’ve shown that orbits near the Earth–Moon L4 and L5 points can survive for over a billion years even when the sun’s gravity is thrown into the mix. However, when the small perturbations from the other planets are present, that can destabilize the orbits at L4 and L5 within several million years. So, they deduced that even though there’s no objects at those points right now, that doesn’t mean there wasn’t something there in the past.

The leading candidate for the theory of the moon’s formation is that a Mars-sized object hit the Earth and the resulting debris formed the moon. The two researchers say other debris would have been present as well, and may have been trapped at the L4 and L5 points.

However, one has to wonder, with the moon, as well as Earth, in a state of flux following the collision, their gravitational fields may have been unstable enough to preclude any L points at the stage where the other debris or moons were in the area. Also, the moon used to be closer to Earth, and the L points would have changed over time, and this change also might have been enough to disengage any “trapped” moons.

But it’s interesting to consider the night sky with multiple moons.

Original News Sources: Icarus, New Scientist

Posted on by Fraser Cain

Finally, Some Help

As you’ve probably noticed, Universe Today has gotten in influx of talented writers to pitch in around here. Tammy Plotner, of course, has been working with me for years, and so have Nancy Atkinson and Mark Mortimer. Ian O’Neill and Nick Wethington are newer contributors, but have definitely proven to be great additions to the team. Thanks to them, I’ve been able to tail back my writing a little to be able to catch up on the world’s longest to-do list.

One huge piece of news, though. As of yesterday, Nancy is now working full time for Universe Today, and will be able to contribute many more stories over the coming weeks and months (dare I say… decades?). Nancy is going to be joining the Astronomy Cast Live team at the upcoming 212th American Astronomical Society meeting in St. Louis from June 1-June 5, 2008, where we’ll try to provide an absurd amount of coverage.

I hope you’ve all noticed and appreciated the jump in quality and coverage from Universe Today, and I’m hoping things will just get better from here.

Fraser Cain
Publisher, Universe Today

Posted on by Fraser Cain

How to Detect Watery Worlds Around Other Stars

The Blue Marble. Image credit: NASA

If you want to know what a watery world might look like orbiting another star, just observe our own planet… from afar. The Blue Marble image of Earth, taken by the Apollo 17 astronauts on December 1972, shows how our planet is 70% water. Another world like ours, orbiting a distant star should be obvious – assuming you have a much more powerful telescope, and use the right techniques to analyze the light bouncing off the watery world.

Researchers from Penn State and the University of Hawaii have developed a technique that they think will help identify these watery worlds; potential homes for life around other stars. This technique is detailed in the most recent edition of the journal Icarus.

“We are looking for Earth-like planets in the habitable zone of their star, a band not too hot nor too cold for life to exist,” says Darren M. Williams, associate professor of physics and astronomy, Penn State Erie. “We also want to know if there is water on these planets.”

Here’s how you might tell the difference between a hellish planet like Venus, and a more comfortable watery world like Earth. A planet like Venus has a very dense atmosphere that scatters sunlight in all directions. From our vantage point, we would see the amount of light coming from the planet change depending on its position to its parent star. Just like Venus, we would see this extrasolar planet go through phases, changing in brightness in a very predictable way.

A watery world, like the Earth, would actually appear much darker when the whole disk is illuminated, since water is darker than dirt. But when the planet is in crescent, sunlight would glance off the surface of the water, and it would actually appear brighter.

The astronomers want to monitor the light curve of a distant planet as it spins on its axis and orbits its star. By watching the brightness of the light coming from the planet, they should be able to determine if it has a dense Venusian atmosphere, or is a better match for a watery world.

The equipment isn’t ready yet, but in the next 10 to 20 years, an observatory will probably be built with enough sensitivity to collect light from Earth-sized planets orbiting other stars. And this method should help determine if they’ll watery worlds, capable of supporting life.

Original Source: Penn State News Release

Posted on by Nancy Atkinson

Only 11 Space Shuttle Missions Remain

Space shuttle Discovery now sits majestically out on launch pad 39A, preparing for the upcoming STS-124 mission to the International Space Station. With the shuttle program slated to terminate in 2010, there’s a limited amount of times we’ll see that sight again: a space shuttle will crawl out to the pad only 10 more times –or possibly only 9 more. And whether that thought chokes you up a bit, or evokes a shout of “It’s about time!” here’s a quick look at the remaining shuttle missions and what each will accomplish. All dates and personnel are subject to change. (Updated 7/7/08)


Mission: STS-124
Proposed Launch Date: May 31, 2008, 5:02 pm EDT
Shuttle: Discovery
Mission Description: Discovery will bring the Kibo Japanese Experiment Module – Pressurized Module (JEM-PM) and the Japanese Remote Manipulator System (JEM-RMS) to the ISS. This is the 10th flight since the Columbia disaster, and the first mission that includes all the design modification to the external tank. Crew: Mark Kelly, Ken Ham, Mike Fossum, Karen Nyberg, Ronald Garan and Akihiko Hoshide, as well as bringing Greg Chamitoff to the station as part of Expedition 18.


Mission: STS-125
Proposed Launch Date: ~ October 8, 2008
Shuttle: Atlantis
Mission Description: Atlantis will fly to the Hubble Space Telescope for the fifth and final servicing mission for the venerable telescope, improving the observatory’s capabilities through 2013. Since the shuttle won’t be going to the ISS, which provides a safe haven in the event of an emergency, another shuttle, Endeavour, must be ready to go at the pad. Hence, the delay from the original launch date of August 28, 2008 as an additional new and improved external tank won’t be ready by then.
Crew: Scott Altman, Greg Johnson, Megan McArthur, Michael Good, John Grunsfeld, Michael Massimino and Andrew Feustel.


Mission: STS-126
Proposed Launch Date: ~ November 10, 2008
Shuttle: Endeavour
Mission Description: Endeavour, on ISS flight ULF2, will deliver supplies to the station in a Multi-Purpose Logistics Module, and execute crew exchange for the ISS.
Crew: Chris Ferguson, Eric Boe, Stephen Bowen, Heidemarie Stefanyshyn-Piper, Don Pettit, R. Shane Kimbrough, as well as bringing Sandra Magnus to the station as part of Expedition 18, and returning Greg Chamitoff back home after his stint as part of Exp. 18.

Mission: STS-119
Proposed Launch Date: February 12, 2009
Shuttle: Discovery
Mission Description: Discovery will bring the fourth starboard truss segment to the ISS on assembly flight 15A, as well as the fourth set of solar arrays and batteries. Click here for a video of how the assembly will be accomplished.
Crew: Lee Archambault, Dominic Antonelli, John Phillips, Steven R. Swanson, Joseph Acaba, Richard Arnold (Acaba and Arnold are Educator Astronauts). Additionally, STS-119 will bring JAXA astronaut Koichi Wakata to the station as part of Expedition 18, and bring home astronaut Sandy Magnus.

Mission: STS-127
Proposed Launch Date: May 15, 2009
Shuttle: Endeavour
Mission Description: Endeavour will deliver and install the final component of the Japanese Experiment Module, the Exposed Facility.
Crew: Mark Polansky, Doug Hurley, Christopher Cassidy, Thomas Marshburn, Dave Wolf, Julie Payette, as well as bringing ISS Expedition 19 Flight Engineer Timothy Kopra to the station and returning Koichi Wakata back home.

Mission: STS-128
Proposed Launch Date: July 30, 2009
Shuttle: Atlantis
Mission Description: Atlantis’ primary payload will be the Italian Multi-Purpose Logistics Module Donatello, which will deliver equipment to allow for bringing the station crew from three to six.
Crew: Not yet set, but currently, Nicole Stott is scheduled to be brought to the station as part of the Expedition 19, and Tim Kopra will get a ride home. The additional astronauts for the increased ISS crew size have not yet been named.


Mission: STS-129
Proposed Launch Date: October 15, 2009
Shuttle: Discovery
Mission Description: Discovery will deliver the first two ExPRESS(Expedite the Processing of Experiments to the Space Station) Logistics Carriers, which allows for “outdoor” experiments at the ISS.
Crew: Not yet named, but astronaut Jeff Williams is scheduled to be brought on board as part of Expedition 20, and Nicole Stott brought home.

Mission: STS-130
Proposed Launch Date: December 10, 2009
Shuttle: Endeavour, (possibly its last flight (see below)
Mission Description: Endeavour will bring supplies to the ISS in the Raffaello Multi-Purpose Logistics Module. No crew for the shuttle or station has yet been named.

Mission: STS-131
Proposed Launch Date: February 11, 2010
Shuttle: Atlantis, on its final flight
Mission Description: Atlantis will deliver the Docking Cargo Module and the third and fourth EXPRESS Logistics Carriers to the ISS on Assembly Flight ULF5.

Mission: STS-132
Proposed Launch Date: April 8, 2010
Shuttle: Discovery, its final flight
Mission Description: deliver the Node 3 components to the ISS, which includes advanced life support systems and a Cupola with a robotic workstation. It’s possible that this flight could be the final space shuttle mission if an additional contingency mission is not needed.

Mission: STS-133
Proposed Launch Date: May 31, 2010
Shuttle: Endeavour (for sure the final flight!)
Mission Description: This is a contingency flight to finish any remaining construction or bring up any remaining components, and possibly bring the 5th ExPRESS Logistics Carrier. If needed, this will be the final space shuttle mission.

Posted on by Fraser Cain

Comet Strikes Increase as We Pass Through the Galactic Plane

There are just so many ways the Universe is out to get us. Astronomers have already considered the threat from our Sun’s orbit around the center of the Milky Way. When our Sun rises up out of flat plane of the Milky Way, it appears we might be less protected from intergalactic radiation and cosmic rays. Well, it looks like passing through the middle of the galactic plane might have its own share of risks: an increased number of comets might be hurled towards the Earth because of gravitational interaction with the densest parts of our galaxy.

Researchers at the Cardiff Centre of Astrobiology have built a computer model of the Solar System’s journey around the Milky Way. Instead of making a perfectly flat orbit around the galaxy’s centre, it actually bounces up and down. At times it can rise right up out of the galactic plane – getting 100 light years above – and then dip down below it. They calculated that we pass through the plane every 35 to 40 million years.

And this time period seems to match dangerous periods of impacts on Earth. According to the number and age of craters on Earth, we seem to suffer increased impacts every 36 million years. Uh oh, that’s a match.

In fact, one of these high points of comet activity would have been 65 million years – the same time that an asteroid strike wiped out the dinosaurs.

And here’s the bad news. According to their calculations, the Solar System will be passing through the galactic plane in the near future, and should see an increased risk of impact. Our risk of impact could increase 10-fold.

There might be a silver lining to the bounce, though. The impacts might have helped life spread across the galaxy.

While the “bounce” effect may have been bad news for dinosaurs, it may also have helped life to spread. The scientists suggest the impact may have thrown debris containing micro-organisms out into space and across the universe.

Centre director Professor Chandra Wickramasinghe said: “This is a seminal paper which places the comet-life interaction on a firm basis, and shows a mechanism by which life can be dispersed on a galactic scale.”

Here’s more info on the story from Bad Astronomy.

Original Source: Cardiff News Release