On rare occasions, I've seen the darkness filling the bowl leavened to a deep gray by sunlight reflecting off the crater's rim. Tycho's floor is 4. It's composed of melted rock called impact melt created by the tremendous heat generated during the impact. The view through a telescope only hints at what's there. To fully appreciate the floor's bizarre humpback mounds of melted rock, wormy troughs, and crisscrossing cracks, visit the LROC-Quickmap site , an interactive, zoomable tool that takes you so close to the Moon you can almost smell it.
High resolution images from LRO were stitched together to create the map. Center the view on Tycho, zoom in with your mouse, and explore. Glassy impact melt extends beyond the crater wall to create the unique dark "collar" around Tycho best visible at full Moon. The collar sets the crater off from a larger nimbus of exceptionally bright rays that overlap and weave in intricate ways. You can almost lose your way here, so take your time.
A neutral density filter will help to tone down the light and make it easier on the eye. Look closely at the craters within and just beyond the dark collar several days before or after full Moon; their floors and walls display narrow, linear gouges that trace the blast tracks of impact debris across the region. What a sight it must have been in the day. Lunar erosion scratches away details relatively slowly, allowing us to appreciate the magnitude of the bombardment to this day.
Tycho's rays form a web of white spokes that extend up to 2, km across the lunar nearside, even as far as Mare Serenitatis, where the Apollo 17 astronauts collected their crucial sample. One possible ray bisects the mare and reaches even further, but it's still unclear if it belongs to Tycho or the crater Bessel , which it overlaps. The rays aren't equally distributed but form a butterfly pattern with most extending to the lunar east, south, and northwest. Very few reach west, indicating that the projectile approached at a low angle from the west to create the off-center ballistic pattern.
A short, bright ray to the south-southwest of Tycho doesn't fit the pattern: instead of pointing back to the crater, it's nearly tangent to it. I've tried hard to imagine what might have happened in the chaos of impact to cause a stream of boulders to turn askew and land in such a non-radial fashion, but I'm still at a loss. Was it redirected after colliding with another ejecta stream? Unrelated to Tycho? A remarkable pair of rays to the crater's northwest upper left run parallel, like the ruts cut by an the old wagon trains across the prairie.
These features and others will be in full view this week during full Moon. But wait, there's more. With two full Moons this month the next falls on March 31st , we'll get to see it all over again!
I've wondered about that tangent ray that goes toward the lunar southwest from Tycho. The point where the tangent ray and the double ray would intersect is just about on the lunar western edge of Tycho.
I can imagine the asteroid coming in from the west at a low angle, kicking up the debris that formed the tangent ray and the double ray, and continuing to plow into the lunar surface and excavate the crater. But that's just a layperson's imagination. I hope the selenologists will figure it out and create a cool animation of the impact. Editor's note: If you have an amazing skywatching photo you'd like to share it with Space. Original article on Space. Join our Space Forums to keep talking space on the latest missions, night sky and more!
And if you have a news tip, correction or comment, let us know at: community space. How old is Tycho? Because the impact event scattered material to such great distances, it's thought that some of the samples at the Apollo 17 landing site originated at the Tycho impact site.
These samples are impact melt glass, and radiometric age dating tells us that they formed million years ago. So if these samples are truly from Tycho, the crater formed million years ago as well. This may still seem old, but compared to the 3. Directly sampling material from within the crater would help us learn more about not just when Tycho formed, but the ages of terrains on other planets throughout the solar system. Planetary surfaces are dated by counting the number of craters on the surface, and comparing that number to the number of craters that formed on a surface for which we know the age by actually sampling the rocks.
The problem is, there aren't that many places for which we've sampled the rocks, and confirming the age of Tycho would help date younger surfaces, which are not well sampled. Tycho is also of great scientific interest because it is so well preserved, it is a great place to study the mechanics of how an impact crater forms. Tycho's central peak is thought to be material that has rebounded back up after being compressed in the impact, and though it's a peak now, it originated at greater depth than any other portion of the crater.
The floor of the crater is covered in impact melt, rocks that were heated to such high temperatures during the impact event that they turned to liquid, and flowed across the floor. In the image below, impact melt flowed downhill and pooled, where it cooled. This illustration taken from the Cassini Grand Finale movie shows Cassini's fly-through of the Enceladus plume in October Cassini at Enceladus Illustration. Presented here is a complete set of cartographic map sheets from a high-resolution Dione atlas, a project of the Cassini Imaging Team.
The map sheets form a quadrangle series covering the entire The Dione Atlas. The Cassini composite infrared spectrometer obtained temperature maps of Saturn's main rings A, B and C that showed ring temperatures decreasing with increasing solar phase angle the change of t Slower Spinning Rings 1. These three posters imagine future tourism possibilities based on the rich history of Saturn exploration from the twin Voyager's Grand Tour to the epic discoveries made by the Cassini-Huygens missi Visions of the Future: Saturn Tour.
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