Comet Siding Spring Animation

Gigantic groundwater outbursts created the largest flood channels in the solar system on Mars, 3.2 billion years ago. For many years it was thought that this was caused by the release of water from a global water table, but research just published reveals regional deposits of sediment and ice emplaced 450 million years earlier to be the source.

The nucleus of the largest known comet in the Solar System, C/2014 UN271 (Bernardinelli–Bernstein), has been measured by the Hubble Space Telescope to be 129 kilometres across.

NASA is close to deciding whether to spend an extra $150 million to send the InSight lander to Mars in 2018 or cancel the mission after an instrument problem made the spacecraft miss a launch opportunity this year, with a verdict on the project’s future expected within weeks, officials said.