— NASA's Hubble confirms that galaxies are the ultimate recyclers — New observations by NASA's Hubble Space Telescope are expanding astronomers' understanding of the ways in which galaxies continuously recycle immense volumes of hydrogen gas and heavy…
— Frozen comet had a watery past, University of Arizona scientists find — For the first time, scientists have found convincing evidence for the presence of liquid water in a comet, shattering the current paradigm that comets never get warm enough to melt…
— Sugar-grain sized meteorites rocked the climates of early Earth and Mars — Bombardments of 'micro-meteorites' on Earth and Mars four billion years ago may have caused the planets' climates to cool dramatically, hampering their ability to support life, according…
— Astrophysicist: White dwarfs could be fertile ground for other Earths — Planet hunters have found hundreds of planets outside the solar system in the last decade, though it is unclear whether even one might be habitable. But it could be that the best place…
— Integral spots matter a millisecond from doom — ESA's Integral gamma-ray observatory has spotted extremely hot matter just a millisecond before it plunges into the oblivion of a black hole. But is it really doomed? These unique observations…
— MESSENGER spacecraft to swing into orbit around Mercury — At 8:45 p.m. EDT on March 17, the MESSENGER spacecraft will execute a 15-minute manoeuvre that will place it into orbit around Mercury, making it the first craft ever to do so, and…
— Baby stars born to 'napping' parents — Cardiff University astronomers believe that a young star's long 'napping' could trigger the formation of a second generation of smaller stars and planets orbiting around it…
— Oldest objects in solar system indicate a turbulent beginning — Scientists have found that calcium, aluminium-rich inclusions (CAIs), some of the oldest objects in the solar system, formed far away from our sun and then later fell back into the…
— Oxygen isotope analysis tells of the wandering life of a dust grain 4.5 billion years ago — Scientists have performed a micro-probe analysis of the core and outer layers of a pea-sized piece of a meteorite some 4.57 billion years old to reconstruct the history of its formation,…
Craters young and old in Sirenum Fossae
The Mars Express High Resolution Stereo Camera has imaged craters both young and old in this view of the Southern Highlands of Mars. Part of the Sirenum Fossae region in the Southern Highlands, the area in this image is centred at about 28 S / 185 E. The image captures an area to the north of the Magelhaens Crater. It extends some 230 km by 127 km and covers about 29 450 sq km, roughly the size of Belgium. The image resolution is approximately 29 metres per pixel.
Sirenum Fossae extends for more than 2500 km to the southwest of the Tharsis volcanic region, which contains Olympus Mons, the highest volcano in our Solar System. Sirenum Fossae is a system of grabens, formed by stresses placed on the crust during the uprising of the Tharsis region. A graben is visible as two sets of parallel lines running from top to bottom to the left of centre.
The Southern Highlands are older than the Northern Lowlands, based on the larger number of impact craters seen to cover the region. Craters of 50 km in diameter are common in this area and have usually suffered from erosion, indicating they were formed during ancient times.
There is an impact crater with a diameter of about 28 km to the left of the image. In contrast to other craters in its vicinity, it has experienced less erosion - its crater rim and central peak are still preserved. There are three other craters nearby: to the west is a large crater with a diameter of 56 km, to the northeast one that stretches 34 km across and a smaller crater of only 9 km diameter to the south.
On the basis of their appearances, the craters can be placed in age order. The largest two are the oldest because they have been partially destroyed by the mid-sized crater. The smallest is the youngest because it has impacted into the rim of the mid-sized crater.
In the central part of the image, a plateau is recognisable and shows evidence of further erosion. In particular, there is a broad valley system on the western slope.
Or subscribe for our Newsletter, a free e-mail publication. It is published practically every day.
Finding twin Earths: Harder than we thought!
NASA's Fermi mission, Namibia's HESS telescopes explore a blazar
Quadruple Saturn moon transit snapped by Hubble
Kepler rockets to space in search of Earth analogues