Road to nowhere (by Jan Gravekamp)
Road to nowhere (by Jan Gravekamp)
Is there life on mars?
A meteorite found in the Sahara, one of the oldest meteorites ever found, gives further evidence to support the theory of extra terrestrial life on mars. The 0.7-pound fragment, NWA 7034, contains more water than any pre-discovered martian meteorites. “It’s about 6,000 parts per million of water,” said Carl B. Agee, director of the institute of Meteoritics, Curator of meteorites and Professor of the department of earth and planetary sciences in New mexico, who led the study. In comparison, there are over 100 martian meteorites discovered, which mostly have 30 times less water content per million. This 320 gram meteorite fragment is currently the most substantial evidence we have of water-based organic life existing on another planet. Using evidence from water molecules locked in the mineral structure, it has been estimated that life could have been supported on mars up to 2 billion years ago. It is suggested that the meteorite exploded from a volcano in the crust of the planet, the water locked in the basalt came from an underground water source near the source of the explosion.
When two bodies orbit around each other in space, we know exactly what happens. The bodies trace out conic sections, they do so in accordance with Kepler’s laws, and that’s it, more or less.
When three or more bodies orbit around each other in space, things can be more complicated. In the general case, no explicit formula for the orbits exists, and we have to rely on numerical simulations. As the first two animations illustrate, these can get messy. (These animations by my friend poulenque.)
Among all these possible orbits, though, there exist some which repeat after some time. These are called n-body choreographies (with n = the number of bodies), small islands of order in a large chaotic space of ways-things-can-be. That’s what all those other animations are. (These animations are by Chris Moore, from here, where he has some others too.)
Most of these are completely unstable, in that the slightest nudge or imbalance in their masses will get amplified until they go flying. However, the one that traces out a figure 8 above is only somewhat unstable, in that (apparently) it will resist small nudges or variations in mass. It is estimated that between 1 and 100 naturally-occurring such figure 8 configurations exist in the entire observable universe.
In all of the animations above except for the second, the masses of all the objects are the same. This is important if you want to wonder about them.
If you approached the rim of a volcano and looked down into it, you might expect to see a lava pool, but if the volcano previously erupted and then the top of it collapsed into a huge bowl-shaped crater, or caldera, then what you might see when you peer over the rim is a beautiful crater lake. Sometimes the water is acidic and the lake has a bright greenish hue. Other times the water is a cloudy turquoise color, yet other times the lake may appear to be a very deep shade of blue. Crater Lake, Oregon, is one of the most well known, but crater lakes can be found all over the globe. If the volcano has been dormant for a long time, the water can be extremely clear because no river or streams flow into with sediment deposits. In some cases, water may have filled up an impact crater to form a lake, but this is less common. A few crater lakes were created by man via an atomic blast, but an artificially-created crater lake is the least common of all. All crater lakes were once a place where the earth experienced great violence, but now are a place of great beauty … even though the volcano can become active and violent again.
Explanation: In silhouette against a crowded star field toward the constellation Scorpius, this dusty cosmic cloud evokes for some the image of an ominous dark tower. In fact, clumps of dust and molecular gas collapsing to form stars may well lurk within the dark nebula, a structure that spans almost 40 light-years across this gorgeous telescopic portrait. Known as a cometary globule, the swept-back cloud, extending from the lower right to the head (top of the tower) left and above center, is shaped by intense ultraviolet radiation from the OB association of very hot stars in NGC 6231, off the upper edge of the scene. That energetic ultraviolet light also powers the globule’s bordering reddish glow of hydrogen gas. Hot stars embedded in the dust can be seen as bluish reflection nebulae. This dark tower, NGC 6231, and associated nebulae are about 5,000 light-years away.
NASA APOD 6 Jan 2013
Gallium is a silvery metal with atomic number 31. It’s used in semiconductors and LEDs, but the cool thing about it is its melting point, which is only about 85 degrees Fahrenheit. If you hold a solid gallium crystal in your hand, your body heat will cause it to slowly melt into a silvery metallic puddle. Pour it into a dish, and it freezes back into a solid.
While you probably shouldn’t lick your fingers after playing with it, gallium isn’t toxic and won’t make you crazy like mercury does. And if you get tired of it, you can melt it onto glass and make yourself a mirror.
Someone get me this for my non-birthday.
NASA - Earth As Art [free ebook/app]