One of the pits in the area called Seth on the surface of the comet 67P/Churyumov-Gerasimenko (Image ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA)

An article published in the journal “Nature” describes a research on a series of 18 pits on the comet 67P/Churyumov-Gerasimenko. They are nearly circular and some of them are a source of activity, emitting jets of gas and dust. They were discovered a long time ago but an analysis of the images collected by ESA’s space probe Rosetta’s OSIRIS camera allowed to establish that probably they were formed following a collapse of the surface.

The Asteroid Day website's home page

Today marks the first Asteroid Day, a day dedicated to raising public awareness about the potential danger posed by asteroids and any space object whose trajectory passes through the Earth’s orbit. The date was chosen because it’s the anniversary of the Tunguska event, the destruction of a large area of ​​Siberia that took place on June 30, 1908 due to the impact of a meteorite or a piece of comet.

The SpaceX Dragon space cargo ship blasting off atop a Falcon9 in its CRS-7 mission (Image NASA)

A flittle while ago the SpaceX Dragon spacecraft blasted off on a Falcon 9 rocket from Cape Canaveral in its CRS-7 (Cargo Resupply Service 7) mission, also referred to as SPX-7. It was supposed to be the seventh mission that sent the Dragon spacecraft to the International Space Station with various a cargo. Unfortunately a couple of minutes after launch something went wrong, causing the destruction of the rocket and the Dragon.

Six of the icy areas on the surface of the comet 67P/Churyumov-Gerasimenko found by the Rosetta space probe (Image ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA)

The OSIRIS (Optical, Spectroscopic, and Infrared Remote Imaging System) camera on ESA’s space probe Rosetta allowed to identify 120 icy areas on the surface of the comet 67P/Churyumov-Gerasimenko. A study of the presence of ice has just been published in the journal “Astronomy & Astrophysics”. That presence was well known but Rosetta’s observations allowed to understand the phases of transformation into gas, how much of it forms the comet’s coma and tail and what falls back to the surface.

Artistic illustration of the planet GJ 436b surrounded by its huge tail and its parent star GJ 436 (Image NASA, ESA, and G. Bacon (STScI))

An article in the journal “Nature” describes a research about the planet GJ 436b, whose mass is similar to that of Neptune. Using the Hubble Space Telescope, a team of astronomers led by David Ehrenreich of the Observatory of the University of Geneva in Switzerland discovered that it leaves behind a huge tail of the estimated size of about 50 times that of the star it orbits. Those are hydrogen emissions ripped from the planet which make it looke like a huge comet.