Astronomers have determined that our own Milky Way galaxy is part of a newly identified ginormous supercluster of galaxies, which they have dubbed "Laniakea," which means "immense heaven" in Hawaiian. This discovery clarifies the boundaries of our galactic neighborhood and establishes previously unrecognized linkages among various galaxy clusters in the local Universe.The Milky Way resides in the outskirts of the supercluster, whose extent has for the first time been carefully mapped using these new techniques. This so-called Laniakea Supercluster is 500 million light-years in diameter and contains the mass of one hundred million billion Suns spread across 100,000 galaxies.
In 1969, the astrophysicists Rashid Sunyaev and Yakov Zel'dovich realized that the then recently discovered cosmic microwave background radiation (CMBR) would be distorted by hot cosmic gas. Hot electrons in the intergalactic medium preferentially scatter the light in one direction, causing a change in the brightness of the CMBR towards clusters of galaxies where electrons should be abundant. They showed that the effect would reveal the large-scale structure of the universe, the nature of the CMBR, cosmological parameters like the Hubble constant, and physical conditions in galaxy clusters.
NASA's Cassini spacecraft has measured a curious abundance of methane spewing into the atmosphere of Saturn's icy moon Enceladus. A team of American and French scientists published findings in Geophysical Research Letters suggesting two scenarios that could explain the methane abundance observed in the plumes.
NASA's Hubble Space Telescope has the best evidence yet for an underground saltwater ocean on Ganymede, Jupiter's largest moon. The subterranean ocean is thought to have more water than all the water on Earth's surface. Identifying liquid water is crucial in the search for habitable worlds beyond Earth and for the search for life, as we know it.
A "chaotic Earth" could exist in a planetary system in which a neighboring planet has "year" that is an integer multiple of another planet's "year," and if the orbital planes are not aligned. The affected planet's orbit can become very elongated and even flip all the way over, such that the two planets are revolving in opposite senses. These planets would have unpredictable climates, perhaps becoming inhospitable for millions of year at a time. Here, the potentially habitable planet is perturbed by a Neptune-mass planet on a three-year orbit and has an elongated orbit, which would make it relatively hot. As such it is mostly dry, but some seas remain, including one which contains the stellar glint, a feature astronomers will look for as it reveals the presence of surface liquids.
A new study by a team of Cassini mission scientists led by the University of Colorado Boulder have found that microscopic grains of rock detected near Saturn imply hydrothermal activity is taking place within the moon Enceladus.The grains are the first clear indication of an icy moon having hydrothermal activity, in which seawater infiltrates and reacts with a rocky crust, emerging as a heated, mineral-laden solution. The finding adds to the tantalizing possibility that Enceladus, one of at least 60 Saturn moons or moonlets and which displays remarkable geologic activity including geysers, could contain environments suitable for living organisms.
"These findings add to the possibility that Enceladus, which contains a subsurface ocean and displays remarkable geologic activity, could contain environments suitable for living organisms," said John Grunsfeld astronaut and associate administrator of NASA's Science Mission Directorate in Washington. "The locations in our solar system where extreme environments occur in which life might exist may bring us closer to answering the question: are we alone in the Universe."
The Milky Way galaxy is at least 50 percent larger than is commonly estimated, according to new findings that reveal that the galactic disk is contoured into several concentric ripples. The research, conducted by an international team led by Rensselaer Polytechnic Institute Professor Heidi Jo Newberg, revisits astronomical data from the Sloan Digital Sky Survey which, in 2002, established the presence of a bulging ring of stars beyond the known plane of the Milky Way.
Magnetic reconnection could be the Universe's favorite way to make things explode. It operates anywhere magnetic fields pervade space--which is to say almost everywhere. In the cores of galaxies, magnetic reconnection sparks explosions visible billions of light-years away. On the sun, it causes solar flares (above) as powerful as a million atomic bombs. At Earth, it powers magnetic storms and auroras. It's ubiquitous. The problem is, researchers can't explain it.