Institute of Astronomy

Astronomy News

Observable Universe contains ten times more galaxies than previously thought [heic1620]

14 October 2016 - 9:17am

Astronomers using data from the NASA/ESA Hubble Space Telescopes and other telescopes have performed an accurate census of the number of galaxies in the Universe. The group came to the surprising conclusion that there are at least 10 times as many galaxies in the observable Universe as previously thought. The results have clear implications for our understanding of galaxy formation, and also help solve an ancient astronomical paradox – why is the sky dark at night?

Hubble Reveals Observable Universe Contains 10 Times More Galaxies Than Previously Thought

14 October 2016 - 9:17am

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In Arthur C. Clarke's novel "2001: A Space Odyssey," astronaut David Bowman exclaims, "My God, it's full of stars!" before he gets pulled into an alien-built wormhole in space. When the Hubble Space Telescope made its deepest views of the universe, astronomers might have well exclaimed: "My God, it's full of galaxies!" The Hubble Ultra Deep Field, for example, revealed 10,000 galaxies of various shapes, sizes, colors, and ages, all within an area roughly one-tenth the diameter of the full moon. What's mind-blowing is that these myriad galaxies, though plentiful, may represent merely 10 percent of the universe's total galaxy population. That's according to estimates from a new study of Hubble's deep-field surveys. The study's authors came to the staggering conclusion that at least 10 times more galaxies exist in the observable universe than astronomers thought.

Our universe contains 10 times more galaxies than we thought

14 October 2016 - 9:16am

The observable universe contains a whopping two trillion galaxies, meaning there may have been a period of rapid galaxy merging in the universe's past

Comet impact 'linked' to rise of mammals

14 October 2016 - 9:15am

A comet impact 55 million years ago may have helped mammals dominate the Earth.

NASA rethinks approach to Mars exploration

13 October 2016 - 9:45am

NASA rethinks approach to Mars exploration

Nature 538, 7624 (2016).

Author: Alexandra Witze

Agency looks to time-allocation model in an era of shifting commercial and international interests.

Planetary science: Moon churn

13 October 2016 - 9:45am

Planetary science: Moon churn

Nature 538, 7624 (2016). doi:10.1038/538177a

Author: Andrew Mitchinson

The Moon's surface is being mapped by NASA's Lunar Reconnaissance Orbiter spacecraft, to aid planning for future missions. On page 215, Speyerer et al. report how images taken by the orbiter's camera have been used to quantify the current rate at which lunar

History: Einstein the statesman

13 October 2016 - 9:45am

History: Einstein the statesman

Nature 538, 7624 (2016). doi:10.1038/538170a

Author: Nancy Thorndike Greenspan

Nancy Thorndike Greenspan enjoys a study of the physicist as engaged public figure.

Quantifying crater production and regolith overturn on the Moon with temporal imaging

13 October 2016 - 9:44am

Quantifying crater production and regolith overturn on the Moon with temporal imaging

Nature 538, 7624 (2016). doi:10.1038/nature19829

Authors: Emerson J. Speyerer, Reinhold Z. Povilaitis, Mark S. Robinson, Peter C. Thomas & Robert V. Wagner

Random bombardment by comets, asteroids and associated fragments form and alter the lunar regolith and other rocky surfaces. The accumulation of impact craters over time is of fundamental use in evaluating the relative ages of geologic units. Crater counts and radiometric ages from returned samples provide constraints with which to derive absolute model ages for unsampled units on the Moon and other Solar System objects. However, although studies of existing craters and returned samples offer insight into the process of crater formation and the past cratering rate, questions still remain about the present rate of crater production, the effect of early-stage jetting during impacts and the influence that distal ejecta have on the regolith. Here we use Lunar Reconnaissance Orbiter Camera (LROC) Narrow Angle Camera (NAC) temporal (‘before and after’) image pairs to quantify the contemporary rate of crater production on the Moon, to reveal previously unknown details of impact-induced jetting, and to identify a secondary impact process that is rapidly churning the regolith. From this temporal dataset, we detected 222 new impact craters and found 33 per cent more craters (with diameters of at least ten metres) than predicted by the standard Neukum production and chronology functions for the Moon. We identified broad reflectance zones associated with the new craters that we interpret as evidence of a surface-bound jetting process. We also observe a secondary cratering process that we estimate churns the top two centimetres of regolith on a timescale of 81,000 years—more than a hundred times faster than previous models estimated from meteoritic impacts (ten million years).

Planetary science: Ocean on another of Saturn's moons

13 October 2016 - 9:44am

Planetary science: Ocean on another of Saturn's moons

Nature 538, 7624 (2016). doi:10.1038/538143f

Like its neighbours Titan and Enceladus, Saturn's moon Dione may harbour an ocean beneath its icy surface.Mikael Beuthe and his colleagues at the Royal Observatory of Belgium in Brussels studied data collected from Enceladus and Dione by NASA's Cassini spacecraft. They looked for small

Astronomy: Strange fading star probed

13 October 2016 - 9:44am

Astronomy: Strange fading star probed

Nature 538, 7624 (2016). doi:10.1038/538143c

A star seems to have been dimming for years, possibly because of a cloud of material obscuring it from view.Benjamin Montet at the California Institute of Technology and Joshua Simon at the Carnegie Observatories, both in Pasadena, used instruments on NASA's Kepler spacecraft to

The Milky Way’s Ancient Heart

13 October 2016 - 9:35am
Ancient stars, of a type known as RR Lyrae, have been discovered in the centre of the Milky Way for the first time, using ESO’s infrared VISTA telescope. RR Lyrae stars typically reside in ancient stellar populations over 10 billion years old. Their discovery suggests that the bulging centre of the Milky Way likely grew through the merging of primordial star clusters. These stars may even be the remains of the most massive and oldest surviving star cluster of the entire Milky Way.

The moon has hundreds more craters than we thought

13 October 2016 - 9:35am

Bombardment by small meteors is constantly churning up the surface of the moon. The dust-up could pose a hazard to future lunar settlements

How to iron out gravity’s creases in our map of the universe

13 October 2016 - 9:33am

Our best map of the big bang’s afterglow is warped. A clean-up technique using light from distant galaxies could clear up some long-standing mysteries

Project Blue plans to send space telescope to snap nearby worlds

13 October 2016 - 9:32am
The mission is to launch a telescope the size of a washing machine and point it in the direction of Alpha Centauri – our neighbouring star system

Disco-ball sail propelled by laser could fly to a nearby star

12 October 2016 - 9:14am

Breakthrough Starshot aims to send an interstellar probe to a neighbouring star system. A design for a laser-propelled sail suggests how that just might work

Weird binary system spotted with three rings around two stars

12 October 2016 - 9:13am

Astronomers have stumbled upon a unique binary system with a disc of gas and dust around each star – and then a third disc circling both

Chicxulub 'dinosaur crater' investigation begins in earnest

12 October 2016 - 9:11am
Scientists begin examining rocks drilled from the crater dug out of Earth's crust by the asteroid impact that killed off the dinosaurs.

Schiaparelli Mars probe 'ready for all eventualities'

11 October 2016 - 9:54am

The European Schiaparelli probe will make its landing attempt on Mars prepared even to handle dust storms if that is what the planet throws up, the mission team says.

CometWatch from Kepler

10 October 2016 - 9:49am

During the last month of Rosetta's operations at Comet 67P/Churyumov-Gerasimenko, it was no longer possible to observe the comet with telescopes on Earth because it was too close to the Sun's position in the sky and therefore not visible in the night-time. Fortunately, NASA's Kepler space observatory stepped in, taking images of the comet every 30 minutes from 7 to 20 September, providing important context to Rosetta's in situ measurements.

The LISA Pathfinder Science Archive is online

10 October 2016 - 9:48am

Today, ESA's LISA Pathfinder Science Archive opens its virtual gates to the world. It contains data collected by the satellite during the mission's first few months, covering the nominal operations phase of the LISA Technology Package (LTP) – the European payload on LISA Pathfinder.