PSI – Astronomy Now

Worldwide pro-am help sought for comet trio study

24 November 2016 Astronomy Now

Amateur and professional astronomers are invited to provide observations of comets 41P/Tuttle-Giacobini-Kresák, 45P/Honda-Mrkos-Pajdušáková, and 46P/Wirtanen that will pass by Earth at distances ranging from 0.08 to 0.15 astronomical units. Such close approaches of a trio of comets within the next two years are rare and typically occur only once every few decades.

Mega-tsunamis ravaged shorelines of ancient Martian ocean

21 May 2016 Astronomy Now

The geologic shape of what were once shorelines through Mars’ northern plains 3.4 billion years ago convinces scientists that two large meteorites – hitting the planet millions of years apart – triggered a pair of mega-tsunamis. These gigantic waves, likely 120 metres high, forever scarred the Martian landscape and yielded evidence of cold, salty oceans.