Since its arrival at comet 67P/Churyumov-Gerasimenko in August 2014, ESA’s Rosetta spacecraft has been surveying the surface and the environment of this curiously shaped body. Now that the comet is experiencing a brief, hot southern hemisphere summer, its south polar regions have emerged from almost five years of total darkness and it has been possible to observe them with other Rosetta instruments.
When a massive star ends its life in a spectacular supernova explosion, it can leave behind a rapidly spinning neutron star with a period of 1-10 milliseconds. Such objects that emit electromagnetic radiation in a lighthouse-like beam sweeping past the Earth are known as millisecond pulsars. CfA astronomers have identified white dwarf companions of two more millisecond pulsars in the spectacular globular cluster 47 Tucanae.
Water reserves found on the Moon are the result of asteroids acting as “delivery vehicles” and not of falling comets as was previously thought. Using computer simulation, scientists from the Moscow Institute of Physics and Technology and the RAS Geosphere Dynamics Institute have discovered that a large asteroid can deliver more water to the lunar surface than the cumulative fall of comets over a billion year period.
When a star collapses forming a black hole, a space-time singularity is created wherein the laws of physics no longer work. In 1965, Sir Roger Penrose presented a theorem where he associated that singularity with so-called ”trapped surfaces” that shrink over time. That hypothesis — one of the results of the general theory of relativity — is now celebrating its 50th anniversary.
At half the diameter of Pluto, Charon is the largest satellite relative to its planet in the solar system. NASA’s New Horizons spacecraft has returned the best colour and the highest resolution images yet of Charon, showing a landscape covered with mountains, canyons, landslides, surface-colour variations and more — all evidence of a surprisingly complex and violent history.
Galaxy clusters are often described by superlatives. After all, they are huge conglomerations of galaxies, hot gas, and dark matter, representing the largest structures in the universe held together by gravity. New observations of the galaxy cluster SPT-CLJ2344-4243 (or Phoenix Cluster) at X-ray, ultraviolet, and optical wavelengths are helping astronomers better understand this extraordinary system.
Earth-like planets orbiting close to small stars probably have magnetic fields that protect them from stellar radiation and help maintain surface conditions that could be conducive to life, according to research from astronomers at the University of Washington just published in the journal Astrobiology.
A new Gemini Observatory image reveals the remarkable “fireworks” that accompany the birth of stars. The picture captures in unprecedented clarity the fascinating structures of a gas jet complex emanating from a stellar nursery at supersonic speeds. Researchers believe they have also found a collection of runaway (orphan) stars that result from all this activity.
The origin of of Comet 67P/Churyumov-Gerasimenko’s double-lobed form has been a key question since Rosetta first revealed its surprising shape in July 2014. By studying the layers of material seen all over the nucleus, scientists have shown that the shape arose from a low-speed collision between two fully fledged, separately formed comets.
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