Category Astronomy/Space

Image of the Whirlpool galaxy, or M51. X-ray light seen by NASA’s Chandra X-ray Observatory is shown in purple, and optical light from NASA’s Hubble Space Telescope is red, green and blue. The ultraluminous X-ray source, or ULX, in the new Caltech-led study is indicated. Credit: NASA/CXC/Caltech/M.Brightman et al.; Optical: NASA/STScI

Astronomers find new clues in galactic mystery of ultraluminous sources of X-rays. In the 1980s, researchers began discovering extremely bright sources of X-rays in the outer portions of galaxies, away from the supermassive black holes that dominate their centers. At first, researchers thought these cosmic objects, called ultraluminous X-ray sources, or ULXs, were hefty black holes with more than ten times the mass of the sun...

An artist’s impression of a flare from Proxima Centauri, modeled after the loops of glowing hot gas seen in the largest solar flares. An artist’s impression of the exoplanet Proxima b is shown in the foreground. Proxima b orbits its star 20 times closer than the Earth orbits the Sun. A flare 10 times larger than a major solar flare would blast Proxima b with 4,000 times more radiation than the Earth gets from our Sun’s flares. Credit: Roberto Molar Candanosa / Carnegie Institution for Science, NASA/SDO, NASA/JPL.

Flare illuminates lack of a dust ring; puts habitability of Proxima b in question. Astronomers have detected a massive stellar flare – an energetic explosion of radiation – from the closest star to our own Sun, Proxima Centauri, which occurred last March...

3 steps astronomers used to measure the universe’s expansion rate (Hubble constant) to an unprecedented accuracy, reducing the total uncertainty to 2.3 percent. The measurements streamline and strengthen the construction of the cosmic distance ladder, which is used to measure accurate distances to galaxies near to and far from Earth. The latest Hubble study extends the number of Cepheid variable stars analyzed to distances of up to 10 times farther across our galaxy than previous Hubble results

Astronomers have used Hubble to make the most precise measurements of the expansion rate of the universe since it was first calculated nearly a century ago. Intriguingly, the results are forcing astronomers to consider that they may be seeing evidence of something unexpected at work in the universe...

Europa has an enormous ocean of warm liquid water under its frozen crust. The bottom of this ocean could be a similar environment to primitive Earth, potentially hosting microorganisms. Credit: NASA

Brazilian scientists compare primitive Earth scenario with satellite Europa’s conditions; the jupiterian moon could host microorganisms at the bottom of a huge warm ocean located underneath its frozen crust. Jupiter’s icy moon Europa is a major target of astrobiology research in light of the possibility that it offers a habitable environment in the Solar System. Under its ice crust, estimated to be 10 km thick, is an ocean of liquid water of over 100 km deep. A huge source of energy deriving from gravitational interaction with Jupiter keeps this water warm.

Theoretical research to evaluate the ...