In a finding that is sure to fuel the ongoing debate about possible life on Mars, NASA announced yesterday the confirmation that intriguing seasonal dark streaks running down Sun-facing slopes are indeed flows of liquid water. The water is salty (briny), but just the fact that it is current liquid water, albeit transient and in relatively small amounts, is still big news.
The question of how Mars changed from a once wet world to the much colder and drier one we see today is one that scientists have been trying to answer for a long time. There is plenty of evidence that Mars use to have lakes and rivers, and perhaps even oceans. But what happened to change that? Now, a new study might bring us one step closer to solving this conundrum.
The fact that Mars used to have large amounts of liquid water on its surface is pretty much accepted among scientists, but there is still the question of how long that water lasted. How long ago was it still present? A billion years? A few million? New evidence based on data from the Mars Reconnaissance Orbiter (MRO) suggests that water was still on the surface within the past million years, perhaps even as recently as 500,000 years ago, which is indeed recent, geologically speaking.
When the topic of ice on Mars comes up, the first thing that usually comes to mind are the polar ice caps which are prominent even in small telescopes. There is, however, ice elsewhere on the planet as well, such as beneath the surface in the mid-latitudes, covered by dust. Now, a new study has revealed the extent of these subsurface glaciers and the amount of frozen water they contain.
This is interesting, a recent HiRISE photo from the Mars Reconnaissance Orbiter spacecraft showing an oval pit or crater with an opening in the bottom (cropped here from one of the larger images) near Galaxias Chaos on Mars. The opening is also oval, and you can see some sand dunes on the bottom. How did it form? More images are available here.
Whether or not Mars once had an ocean has been a subject of much debate for many years. There is substantial evidence pointing toward the possibility, but no “smoking gun” yet. Now, a new discovery from scientists at the California Institute of Technology (Caltech) is fueling that debate again – an ancient delta that appears to have emptied into the hypothetical ocean in the northern hemisphere.
A “missing” Mars lander and its associated hardware from the 1970s may have finally been discovered in images taken by the Mars Reconnaissance Orbiter. The Soviet Mars 3 lander was the first successful landing on Mars by any spacecraft, but after transmitting for only 14.5 seconds after touchdown on December 2, 1971, it went silent and was never heard from again. Its exact landing site was unknown, but now may have finally been located after all these years.
The Curiosity rover has returned yet more images of Mount Sharp, and these are the best and highest-resolution ones yet. Taken by the 100-millimeter Mastcam camera, they show the layering of the mesas in the foothills in incredible detail. Also note the tiny speck in the centre of the white box in the middle of the image (magnified in the bottom corner of the image); that is a boulder about the same size as the rover, which is car-sized, giving a sense of scale. These mesas are huge, and they are dwarfed by the rest of the mountain itself! The images above and below have been enhanced to show the colours as they would appear if they were on Earth. Click on the images for larger versions.
The image below is an orbital view from Mars Reconnaissance Orbiter showing the same region of foothills. This is where Curiosity will be driving later on; the mesas and canyons will be seen up close providing views never seen before by a rover on Mars. There is also a channel cutting through the middle portion of the image, which is thought to be an ancient riverbed. Other similar channels and their alluvial deposits can be seen elsewhere in this region. Click on the image for larger version and then click to zoom in.