Category Astronomy/Space

Size comparison between Earth and the exoplanet GJ1214b. Credit: NASA/JPL-Caltech/R. Hurt (SSC)

A nearby exoplanet has an atmosphere that might be similar to Earth’s before life evolved. Scientists have catalogued nearly 2,000 exoplanets around stars near and far. While most of these are giant and inhospitable, improved techniques and spacecraft have uncovered increasingly smaller worlds.

But size alone is insufficient to judge a globe. Though Earth and Venus are nearly identical in size, the latter’s surface is hot enough to melt lead. Astronomers must gather information about an exoplanet’s atmosphere, often through observing how the planet scatters or absorbs light from its parent star. But, that information is not always useful – as is the case with the exoplanet GJ1214b.

“When an exop...

This chronographic map of the Milky Way’s halo system shows a color gradient that is associated with an age difference of roughly 2-2.5 G yrs

The 1st chronographic (age) map of the halo of the Milky Way galaxy has been created. The halo, along with the disk and bulge, are the primary components of the galaxy. Using a sample of 4,700 blue horizontal-branch (BHB) stars from the Sloan Digital Sky Survey, the research team showed that the oldest stars are concentrated in the central region of the galaxy, confirming predictions from numerical simulations of galaxy assembly. The researchers have also shown that chronographic maps such as theirs can also be used to identify complex structures of stars still in the process of being added to the halo system of our galaxy.

The researchers used the...

Rosetta’s detection of molecular oxygen

ESA’s Rosetta spacecraft has made the 1st in situ detection of oxygen molecules outgassing from a comet, a surprising observation that suggests they were incorporated into the comet during its formation.

Rosetta has been studying Comet 67P/Churyumov–Gerasimenko for over a year and has detected an abundance of different gases pouring from its nucleus. Water vapour, CO and CO2 are the most prolific, with a rich array of other N-, S- and C-bearing species, and even ‘noble gases’ also recorded...

Artist’s impression of a fifth giant planet being ejected from the solar system. Image credit: Southwest Research Institute

The existence of a 5th giant gas planet at the time of the Solar System’s formation – in addition to Jupiter, Saturn, Uranus and Neptune that we know of today – was first proposed in 2011. But if it did exist, how did it get pushed out? For years, scientists have suspected the ouster was either Saturn or Jupiter.

“Our evidence points to Jupiter,” said Ryan Cloutier
Planet ejections occur as a result of a close planetary encounter in which one of the objects accelerates so much that it breaks free from the massive gravitational pull of the Sun...