They have smooth surfaces, dark hues, and a general paucity of superposed impact craters
. Most maria lavas erupted between about 3.8 and 2.5 billion years ago, lying within large impact basins whose rims are best seen at the curved Apennine and Altai mountain ranges.
Ancient impact craters
on Mars were probably also home to hydrothermal activity, making them good places to search for signs of life, the team reports February 19 in Geochimica et Cosmochimica Acta.
The UK has had no significant meteorite impact craters
- until now.
"It's very rare," Sharpton continues, "that you find an object large enough to make it through Earth's atmosphere and strike the Earth with such velocity that it produces a crater." But the 150 impact craters
scientists have mapped around the globe over the past 50 years are evidence that such collisions do occur.
Meanwhile, the new impact crater
wasn't the only one discovered on the Mars surface over the past few months.
"For example, we found an 18-meter (59-foot) impact crater
that formed on March 17, 2013, and it produced over 250 secondary impacts, some of which were at least 30 kilometers (18.6 miles) away," Speyerer told (http://www.space.com/34372-new-moon-craters-appearing-faster-than-thought.html) Space.com .
Manuel Roda from Utrecht University said that about 3.5 billion years ago, the pristine Aram impact crater
was partly filled with water ice that was buried under a two-kilometer thick layer of sediment.
The largest impact crater
on record is the Vredefort crater in South Africa which measures 298 kilometres, followed by the Sundbury crater in Canada at 250 kilometres.
M3 imaged the lunar impact crater
Bullialdus, which lies near the lunar equator.
<div class="imageBox" style="width: 516px;"><img id="5439" class="imgPhoto" src="http://img.ibtimes.com/www/data/articles/full/2009/10/09/5439.jpg" alt="LCROSS impact crater
as seen with the visible light camera.
Have they considered that James Bay and Hudson Bay look remarkably like what you'd expect an impact crater
to look like?
The mining town of Middlesboro, Kentucky, sits on the floor of a 3-mile-wide (5 km) impact crater
that interrupts a bit of the folded Appalachian Mountains.