SPACE: WHERE ARE WE GOING? : FROZEN CARBON DIOXIDE

Saturday, June 22, 2013

STRANGE MARS

FROM: NASA

We were looking at these strange features on Mars. They're what we call, "linear gullies," because they're long troughs. They can extend up to two kilometers, which is just over a mile and they're really strange because they go down and then they end abruptly in a pit.

A lot of features on the Earth that are similar do end in a debris apron because stuff has been moved from the top to the bottom. But these don't have the apron. They just have a pit at the end. And so we were wondering how they could form.

Frozen carbon dioxide accumulates on the surface and we think that some of this accumulation will compress down and actually form ice slabs and ice blocks.

We bought some frozen carbon dioxide dry ice blocks and we took it out to a dune slope, and we put it down and we saw what happened.

Most dune slopes will be at 33 degrees and that's a nice steep slope. And so we did it with a water ice block and the sand got wet and it didn't move. And we did it with a wooden block and, you know, it moved three inches and then it stopped.

The dry ice block, we expected it to see a bit more activity, but we didn't expect it to just move and move and move and move and keep moving all the way to the bottom. But even on the other side of the dune, which is more like six degrees -- it's very shallow -- we put the block on and we pushed it and it would just slide right down and the only reason it stopped was because it hit the bushes at the bottom.

Dry ice, as it heats up, turns into gas that pushes against the sand as it comes out. After a few hours, it's scooped out a nice little area. And so you have a feature that looks like what we see on Mars. They will move down that dune slope and carve out a shallow trough.

When the block of ice is on the sand surface, that sand is just a little bit warmer. And so it causes a cushion of air to form. And that lifts that block just a little bit so when it moves forward, it's like its lubricated and it can just slide very easily.

And when it got to the bottom, instead of just sitting there, it would disappear as the area heated up and then that could possibly leave a pit.

I'm looking forward to the day when astronauts can engage in a whole new area of extreme sports. They could snowboard down these carbon dioxide covered dunes on a cushion of carbon dioxide. They would just shoot right down those slopes. It would be amazing.

STAR FLASH

What caused this outburst of V838 Mon? For reasons unknown, star V838 Mon's outer surface suddenly greatly expanded with the result that it became the brightest star in the entire Milky Way Galaxy in January 2002. Then, just as suddenly, it faded. A stellar flash like this had never been seen before -- supernovas and novas expel matter out into space. Although the V838 Mon flash appears to expel material into space, what is seen in the above image from the Hubble Space Telescope is actually an outwardly moving light echo of the bright flash. In a light echo, light from the flash is reflected by successively more distant rings in the complex array of ambient interstellar dust that already surrounded the star. V838 Mon lies about 20,000 light years away toward the constellation of the unicorn (Monoceros), while the light echo above spans about six light years in diameter. Image Credit: NASA, ESA

THE SPIDERWEB GALAXY

Looking like a spider's web swirled into a spiral, Galaxy IC 342 presents its delicate pattern of dust in this image from NASA's Spitzer Space Telescope. Seen in infrared light, faint starlight gives way to the glowing bright patterns of dust found throughout the galaxy's disk. At a distance of about 10 million light-years, IC 342 is relatively close by galactic standards, however our vantage point places it directly behind the disk of our own Milky Way. The intervening dust makes it difficult to see in visible light, but infrared light penetrates this veil easily. IC 342 belongs to the same group as its even more obscured galactic neighbor, Maffei 2. IC 342 is nearly face-on to our view, giving a clear, top-down view of the structure of its disk. It has a low surface brightness compared to other spirals, indicating a lower density of stars (seen here as a blue haze). Its dust structures show up much more vividly (red). Blue dots are stars closer to us, in our own Milky Way. New stars are forming in the disk at a healthy rate. The very center glows especially brightly in the infrared, highlighting an enormous burst of star formation occurring in this tiny region. To either side of the center, a small bar of dust and gas is helping to fuel this central star formation. Data from Spitzer's infrared array camera are shown in blue (3.6 microns), green (4.5 microns) and red (5.8 and 8.0 microns). Image Credit: NASA/JPL-Caltech

JUMPING TO WARP SPEED

This cockpit view of a hypothetical spacecraft traveling at eight-tenths the speed of light shows the visual distortions that would be experienced at such high speeds. The star field is actually being wrapped toward the front of the craft in addition to being significantly blue-shifted. NASA Glenn leads the Breakthrough Propulsion Physics Project, NASA's primary effort to produce near-term, credible, and measurable progress toward the technology breakthroughs needed to revolutionize space travel and enable interstellar voyages. NASA Lewis (now Glenn) Research Center, Cleveland, Ohio.

OBSERVATION FROM THE SPACE STATION