21 March 2020 | New Scientist | 29Martian mystery
Photograph Mars
Reconnaissance Orbiter
Agency NASA
RAVAGED by the largest dust
storms in the solar system and
with temperatures that can fall to
around -125°C, the surface of Mars
is a hostile place. But what about
beneath the ground – what might
lurk there?
This image of an unusual crater
on the slopes of Mars’s Pavonis
Mons volcano was captured in
2011 by the Mars Reconnaissance
Orbiter, which is still surveying the
Red Planet. NASA has reposted the
image on its blog to stimulate
fresh discussion about the crater.
The 35-metre-wide hole at
the centre of the crater opens
to an underground cavern that is
protected from extreme weather
conditions, so may be more likely
to have once housed life. It is
thought to have been almost
90 metres deep before debris
within the crater above fell in and
filled some of the cavern. Now it is
probably around 28 metres deep.
No one yet knows how the
crater formed. It could have been
created by past volcanic activity
on Pavonis Mons, which, at more
than 14,000 metres high, is nearly
1.5 times taller than Earth’s Mount
Everest. Lava that once flowed
from the volcano hardened on
the outside, while the lava below
this continued to flow, forming
structures called lava tubes, which
could have resulted in the crater.
NASA says such caves are key
targets for future exploration
by robots and spacecraft – and
perhaps even humans. ❚
Gege Li