Opportunity has less than four football fields' distance of driving to reach the top of the valley after departing Cape Tribulation, a raised segment about 3 miles (5 kilometers) long on the crater's western rim.Ī grooved ridge called "Rocheport" on the rim of Mars' Endeavour Crater spans this stereo scene from NASA's Mars rover Opportunity. The crater is about 14 miles (22 kilometers) in diameter, with a segmented rim that exposes the oldest rocks ever investigated in place on Mars. It cuts downward west to east across the western rim of Endeavour Crater. Perseverance Valley is about two football fields long. We want to see as many features like this on the way to Perseverance Valley as we can, for comparison with what we find there." They may have been carved by water or ice or wind. "Grooves run perpendicular to the crest line. "The degree of erosion at Rocheport is fascinating," said Opportunity Deputy Principal Investigator Ray Arvidson, of Washington University in St. This version of the scene is presented in enhanced color to make differences in surface materials more easily visible. For anyone interested, here’s a Wikipedia page listing all the largest craters known to exist in the Solar System.A grooved ridge called "Rocheport" on the rim of Mars' Endeavour Crater spans this scene from the Pancam on NASA's Mars rover Opportunity. Apparently the largest impact basin in the Solar System is Utopia Planitia on Mars. Here’s an article from, going into a little more detail about how Caloris Basin formed and what we currently know about it.Īnd here’s an article from Wondrium about the Late Heavy Bombardment, how it happened, and how we know about it.Īlso, I thought I read somewhere that Caloris Basin was the largest impact basin in the Solar System, and an early draft of this blog post included that detail. MESSENGER revealed that its actually 1550 km (960 miles) in diameter, making it even more larger than Texas. So the full size of the crater remained uncertain until the 2010’s, when the MESSENGER Mission entered orbit of Mercury and finally imaged the entire crater in full daylight.īased on Mariner 10’s data, scientists originally guessed that Caloris Basin was 1300 km (810 miles) in diameter, making it larger than Texas. And it was always the same half of Caloris Basin, too. You may recall from yesterday’s post that Mariner 10 visited Mercury three times, but due to an unfortunate coincidence of orbital mechanics, Caloris Basin was only half in daylight every single time Mariner 10 showed up. At the time of the discovery, Caloris Basin was only half in daylight, so the full size of the crater was unknown. That impact must have been a truly Earth-shattering Mercury-shattering event, sending ripples and shockwaves all the way around the planet, leaving geological marks that can still be seen to this day.Ĭaloris Basin was discovered in 1974 by NASA’s Mariner 10 space probe. We know this must have been near the end of the Late Heavy Bombardment because Caloris Basin has only a few smaller, younger-looking craters inside it, while the surrounding terrain is thoroughly peppered with older-looking craters. Earth’s Moon took a beating, too.Ī particularly large asteroid must have slammed into Mercury near the end of the Late Heavy Bombardment. All the inner planets (Mercury, Venus, Earth, and Mars) took a beating. All those gravitational tug-of-wars in the outer Solar System sent tons and tons and tons of stray asteroids hurtling toward the inner Solar System. The gas giants (Jupiter, Saturn, Uranus, and Neptune) were engaged in these gravitational tug-of-wars with each other, pulling each other into new orbits, swapping places with each other, and generally causing chaos in the outer Solar System-and generally making a mess of the inner Solar System, too. So how did Mercury end up with such a big crater?īased on what science currently knows about the history of the Solar System in general, and the history of Mercury in particular, Caloris Basin most likely formed during an event known as the Late Heavy Bombardment.Ībout four billion years ago, the Solar System looked a little different than it does today. And as for Mercury, Mercury has Caloris Basin, an absurdly large crater in Mercury’s northern hemisphere. Mars has both Olympus Mons and Valles Marineris, the largest volcano and the largest canyon, respectively, in the entire Solar System. It seems like just about every planet has its thing. Hello, friends! For this year’s A to Z Challenge, we’re exploring the planet Mercury.
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |