Stories tagged Seven Sisters


Skylights to possible Mars caves

NASA's Mars Odyssey spacecraft has discovered entrances to seven possible caves on the slopes of a Martian volcano.

Hot spots

Mars "caves": Image credit: NASA/JPL-Caltech/ASU/USGS
Mars "caves": Image credit: NASA/JPL-Caltech/ASU/USGS
Using infrared imaging, the holes showed up as bright "hot spots" in photos taken during the cold of night (see right hand photo). In daytime shots they were colder than their surroundings (middle photo). The left photo uses the visable spectrum. This possible cave skylight informally called "Annie," has a diameter about double the length of a football field.

Seven Sisters

Seven Sisters
Seven Sisters
The discovered holes, dubbed "Seven Sisters," are at some of the highest altitudes on the planet, on a volcano named Arsia Mons near Mars' tallest mountain.

What are they?

A report of the discovery of the possible cave skylights by Cushing and his co-authors was published online recently by the journal Geophysical Research Letters.

The new report proposes that the deep holes on Arsia Mons probably formed as underground stresses around the volcano caused spreading and faults that opened spaces beneath the surface. Some of the holes are in line with strings of bowl-shaped pits where surface material has apparently collapsed to fill the gap created by a linear fault.