Brown dwarfs are sometimes called failed stars as they are too small to sustain the hydrogen fusion process that powers stars. Their temperatures can range from nearly as hot as a star to as cool as a planet and their masses also range between star-like and giant-planet-like. A near-infrared survey has discovered several ultracool brown dwarfs in the Sun’s vicinity.
How did carbon-based life develop on Earth, given that most of the planet’s carbon should have either boiled away in the planet’s earliest days or become locked in Earth’s core? A new study suggests all of the planet’s life-giving carbon came from a collision with an embryonic planet similar to Mercury approximately 4.4 billion years ago.
Less than a month before the end of the mission, Rosetta’s high-resolution camera has revealed the Philae lander wedged into a dark crack on Comet 67P/Churyumov–Gerasimenko. The images were taken on 2 September by the OSIRIS narrow-angle camera as the orbiter came within 2.7 kilometres of the comet’s surface.
Combining images taken with the NASA/ESA Hubble Space Telescope over more than 20 years, a team of researchers has discovered that Eta Carinae, a very massive star system that has puzzled astronomers since it erupted in a supernova-like event in the mid-19th century, has a past that’s much more violent than they thought.
ESA’s Planck satellite has revealed that the first stars in the universe started forming later than previous observations of the Cosmic Microwave Background indicated. This new analysis also shows that these stars were the only sources needed to account for reionising atoms in the cosmos, having completed half of this process when the universe had reached an age of 700 million years.
A new record for the most distant galaxy cluster has been set using NASA’s Chandra X-ray Observatory and other telescopes. CL J1001+0220 is located about 11.1 billion light-years from Earth. The discovery of this object pushes back the formation time of galaxy clusters — the largest structures in the universe held together by gravity — by about 700 million years.
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