THE GREAT TYCHO ZOOM 1-4
Photo Credit: NASA Lunar Reconnaissance Orbiter (LRO): CLICK for larger photo and look below for links and information.
I think the last ZOOM series I did was the globular star cluster of Omega Centauri so it’s time for another one. This time it’s one we can all look up and see, especially if you have binoculars and or a telescope. We’re going to do a 4-part zoom-in on Tycho Crater of the Moon.
1-4: LRO wide angle image (actually a mosaic) of Tycho Crater spans approximately 80.7 mi (130 km) wide and north is up. In this image you can see the sharply defined structure of the rim and central peak. The floor is covered in impact melt and the slopes of the walls are very steep. The arrow in the photo is actually pointing out impact melt on the floor of the crater but it’s also pointing directly at the central peak region. What you can’t see here is the level of albedo in the ejecta “spokes” or “rays” that stream out in all directions which you can see in binoculars or a telescope. I debated making this a 5-part zoom so I could detail that but decided to stick with the 4.
Tycho Crater is a paraboloid shaped, complex impact crater on the Moon which bears the name of the great Danish astronomer Tycho Brahe. The name was given by Giovanni Riccioli whose 1651 lunar nomenclature system is todays standard. It was formed on the approximately 110 million years ago which is very young in astronomical terms. It’s approximately 51 mi (82 km) in diameter with a depth of 2.9 mi (4.8 km). When viewed through binocular or telescope the albedo alerts you to its young age as its interior and ejecta “spokes” or “rays” appear to overlay the surrounding environment as they stretch as long as 932 mi (1500 km), especially when in sunlight.
One of the most incredible features is the uplift or rebound area at the crater’s center known as the central peak. It stretches about 9.3 mi (15 km) and rises off the crater floor to a height of 6562 ft. while the crater floor itself lies 15,420 ft. (4700 m) below the rim.
The rigidity and sharpness to the structure also lends itself to a young crater as it hasn’t yet been worn away by micrometeorites as it will through the years (to see what this crater may look like in a billion years check out Bhabha crater). It’s believed but not proven that this crater was created from the Baptistina family of asteroids, caused by the breakup and multiple impacts of asteroid 298 Baptistina. That is the asteroid which is believed to have also created the 110 mi (180 km) wide Chicxulub Crater in the Yucatan Peninsula on Earth which ended the era of the dinosaurs. Note that it’s believed to be the same material, this doesn’t imply that it happened at the same time as it’s estimated that the Chicxulub Crater was formed approximately 65-66 million years ago.
To locate Tycho Crater, Northern Hemisphere sky watchers will want to look near the very bottom of the Moon while my upside down friends in the Southern Hemisphere will need to search near the top of the Moon. In both cases it will be the brightest most prominent crater in that region. Its selenographic coordinates are 43.37°S, 348.68°E.
NASA LRO page for this crater: http://lroc.sese.asu.edu/news/?archives/411-Tycho-Central-Peak-Spectacular!.html
Incredible NASA LRO Tycho peak interactive zoom: http://wms.lroc.asu.edu/lroc_browse/view/M162350671
Impact melt on Tycho floor: http://lroc.sese.asu.edu/news/index.php?/archives/319-Impact-melt-features-in-Tycho-craters-floor.html#extended