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Proof that some galaxies are LIERs

You might think that astronomers could easily tell the difference between a black hole and a white dwarf — but nature can be deceptive. Astronomers from the Sloan Digital Sky Survey (SDSS) have just announced the results of a new study that reveals the true origin of puzzling light from nearby galaxies.

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Martian starburst spiders

Mars’ seasonal cap of carbon dioxide ice has eroded many beautiful terrains as it sublimates (goes directly from ice to vapour) every spring. In the region where the High Resolution Imaging Science Experiment (HiRISE) camera on NASA’s Mars Reconnaissance Orbiter took this image, we see troughs that form a starburst pattern.

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A galactic mega-merger

The subject of this NASA/ESA Hubble Space Telescope image is known as NGC 3597. It is the product of a collision between two good-sized galaxies, and is slowly evolving to become a giant elliptical galaxy. This type of galaxy has grown more and more common as the universe has evolved, with initially small galaxies merging and progressively building up into larger galactic structures over time.

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‘X’ marks a curious corner on Pluto’s icy plains

“X” marks the spot of some intriguing surface activity in the latest picture of Pluto returned from NASA’s New Horizons spacecraft. This image from the Long Range Reconnaissance Imager (LORRI) extends New Horizons’ highest-resolution views of Pluto to the very centre of Sputnik Planum, the informally named icy plain that forms the left side of Pluto’s “heart” feature.

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The case of the missing quasar

Astronomers can’t find any sign of the black hole at the centre of the quasar SDSS J1011+5442, and they couldn’t be happier. The black hole is still there, of course, but over the past ten years, it appears to have swallowed all the gas in its vicinity. With the gas consumed, researchers were unable to detect the spectroscopic signature of the quasar, which now appears as an otherwise normal galaxy.

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Making galactic history with first global age map of the Milky Way

Astronomers have created the first large-scale map that shows stellar ages in the Milky Way by determining the ages of nearly 100,000 red giant stars, at distances of up to 50,000 light-years from the galactic centre. Notably, the map confirms that our home galaxy has grown inside out: in the present epoch, most old stars can be found in the middle, more recently formed ones in the outskirts.

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Most distant massive galaxy cluster identified

The early universe was a chaotic mess of gas and matter that only began to coalesce into distinct galaxies hundreds of millions of years after the Big Bang. It would take several billion more years for such galaxies to assemble into massive galaxy clusters — or so scientists had thought. Now astronomers have detected a massive, sprawling, churning galaxy cluster that formed only 3.8 billion years after the Big Bang, some 10 billion light years from Earth.

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Galaxy quakes could improve hunt for dark matter

Ripples in gas at the outer disc of our galaxy have puzzled astronomers since they were first revealed by radio observations a decade ago. Now, astronomers believe they have found the culprit — a dwarf galaxy, containing dark, unseen material, which skimmed the outskirts of the Milky Way a few hundred million years ago. This method to characterise dark matter marks first real application of galactoseismology.