Hubble bubble, dusty dwarf and more
HUBBLE BUBBLE The combined view of visible and x-ray light from a pair of NASA telescopes has helped astronomers solve a cosmic mystery: What caused the brilliant supernova that left behind this bubble in space? Astronomers already knew that the supernova remnant 0509-67.5 they saw was the product of what’s called a Type Ia supernova, which involves a white dwarf star becoming so massive that it explodes. The most common explanation for a Type Ia is that a white dwarf gains mass by siphoning matter from a companion star.
But in this case, the sharp eyes of the Hubble Space Telescope and the Chandra X-ray Observatory couldn’t find any trace of such a companion. Instead, astronomers think that SNR 0509-67.5 was formed when two tightly orbiting white dwarfs spiralled in toward each other and collided, destroying both stars in a cataclysmic blast.
DUSTY DWARF A new composite picture reveals where things are heating up in the dwarf galaxy known as the Large Magellanic Cloud, a satellite galaxy of our own Milky Way.
Infrared data from NASA’s Spitzer Space Telescope show the warmest regions of the cloud in blue. These are spots where radiation from newborn stars is heating the surroundi n g dust.
T h e coolest parts of the dwarf – where star formation is either just starting or has already quit – appear red, thanks to data from the European Space Agency’s Herschel space observatory.
MOON SHOT The International Space Station seems to hover over the nearly full moon in a newly released picture taken from near Houston, Texas, on January 4
At the time, the space station was flying about 243 miles (391 kilometres) above Earth’s surface. By contrast, the average distance between Earth and the moon is 238,854 miles (384,399 kilometres).
MASKED ROYALTY In a newly released mosaic picture, NASA’s Wide-field Infrared Survey Explorer, or WISE, space telescope helps royals blend in with a crowd: the bright stars of the constellations Cassiopeia and Cepheus seem to vanish among the millions of other stars and dense clouds of dust revealed by the spacecraft’s infrared vision.
Cassiopeia and Cepheus were named after a mythological queen and king of Ethiopia. To the naked eye, the constellations are easily visible in the northern sky every night for most US observers.
ROUND THE BEND You won’t see it here (because NASA’s Solar Dynamics Observatory couldn’t), but a solar flare ushered in the new year on the far side of the sun. What you can see in this ultraviolet picture is a related, massive arc of expelled solar particles on January 2 – the product of a coronal mass ejection, or CME.
This CME was pointed away from Earth, but when our planet is in the line of fire, charged solar particles can cripple satellites, disrupt power grids, and – on the bright side – trigger auroras as the particles interact with molecules in Earth’s atmosphere.
DEFROSTING DUNES Dark starbursts pepper the otherwise bright dunes of Mars’s north polar region in a newly released picture from NASA’s M a r s Reconnaissance Orbiter.
The crescentshaped dunes appear bright because they are coated with carbon dioxide frost. But as winter leaves the northern hemisphere of the red planet, this frost is starting to sublimate, or turn directly from a solid to a gas.
The dark spots show where enough frost has vanished to reveal the basaltic sand underneath.
BIRTHING GROUNDS A new infrared picture allows astronomers to peer inside the roiling sea of star birth in Cygnus X, one of the most active stellar nurseries in our Milky Way galaxy. This turbulent region of gas and dust lies 4,500 lightyears away in the constellation Cygnus, the Swan.
Dust generally blocks visible light, but infrared light passes through, so the new picture – from NASA’s Spitzer Space Telescope – reveals objects and structures that are otherwise impossible to see. For instance, embryonic stars blanketed by dust pop out in the frame, and pillars of dense dust carved by massive stars’ radiation are sharply defined.