Institute of Astronomy

Astronomy News

Planetary science: Many collisions made the Moon

12 January 2017 - 1:34pm

Planetary science: Many collisions made the Moon

Nature 541, 7636 (2017). doi:10.1038/541137e

The Moon may have been formed not from one big cosmic smash, as the leading theory holds, but from multiple smaller collisions.Billions of years ago in the early Solar System, space debris would have collided with the young Earth. Using computer simulations, a team

China plans telescope to hunt for primordial gravitational waves

12 January 2017 - 1:33pm
Located at 5250 metres above sea level in Tibet, Ngari-1 will hunt for gravitational waves that should have been thrown out by the big bang

‘Alien megastructure’ signal may be due to star eating a planet

10 January 2017 - 9:24am

Tabby’s star’s odd blinking and fading has been put down to alien signals and swarms of comets, but devouring a planet could explain everything

New candidate for 'missing element' in Earth's core

10 January 2017 - 9:21am

Scientists believe they have established the identity of a "missing element" in the Earth's core.

Milky Way’s core could be spewing out planet-sized star chunks

9 January 2017 - 9:32am

The supermassive black hole at the galaxy's heart can stretch and shred stars that approach – then fling the shreds away as spheres as small as Neptune

Stephen Hawking says he has a way to escape from a black hole

9 January 2017 - 9:31am

Researchers have long struggled to resolve what happens to information when it falls inside a black hole, but the famous physicist says he has a solution

Hubble Captures 'Shadow Play' Caused by Possible Planet

9 January 2017 - 9:31am

Eerie mysteries in the universe can be betrayed by simple shadows. The wonder of a solar eclipse is produced by the moon's shadow, and over 1,000 planets around other stars have been cataloged by the shadow they cast when passing in front of their parent star. Astronomers were surprised to see a huge shadow sweeping across a disk of dust and gas encircling a nearby, young star. They have a bird's-eye view of the disk, because it is tilted face-on to Earth, and the shadow sweeps around the disk like the hands moving around a clock. But, unlike the hands of a clock, the shadow takes 16 years to make one rotation.

Hubble has 18 years' worth of observations of the star, called TW Hydrae. Therefore, astronomers could assemble a time-lapse movie of the shadow's rotation. Explaining it is another story. Astronomers think that an unseen planet in the disk is doing some heavy lifting by gravitationally pulling on material near the star and warping the inner part of the disk. The twisted, misaligned inner disk is casting its shadow across the surface of the outer disk. TW Hydrae resides 192 light-years away and is roughly 8 million years old.

Mars should have loads more water – so where has it all gone?

6 January 2017 - 9:17am

We have either misunderstood what its early years were like – or it is hiding vast amounts of water beneath its surface

A direct localization of a fast radio burst and its host

5 January 2017 - 9:23am

A direct localization of a fast radio burst and its host

Nature 541, 7635 (2017). doi:10.1038/nature20797

Authors: S. Chatterjee, C. J. Law, R. S. Wharton, S. Burke-Spolaor, J. W. T. Hessels, G. C. Bower, J. M. Cordes, S. P. Tendulkar, C. G. Bassa, P. Demorest, B. J. Butler, A. Seymour, P. Scholz, M. W. Abruzzo, S. Bogdanov, V. M. Kaspi, A. Keimpema, T. J. W. Lazio, B. Marcote, M. A. McLaughlin, Z. Paragi, S. M. Ransom, M. Rupen, L. G. Spitler & H. J. van Langevelde

Fast radio bursts are astronomical radio flashes of unknown physical nature with durations of milliseconds. Their dispersive arrival times suggest an extragalactic origin and imply radio luminosities that are orders of magnitude larger than those of all known short-duration radio transients. So far all fast radio bursts have been detected with large single-dish telescopes with arcminute localizations, and attempts to identify their counterparts (source or host galaxy) have relied on the contemporaneous variability of field sources or the presence of peculiar field stars or galaxies. These attempts have not resulted in an unambiguous association with a host or multi-wavelength counterpart. Here we report the subarcsecond localization of the fast radio burst FRB 121102, the only known repeating burst source, using high-time-resolution radio interferometric observations that directly image the bursts. Our precise localization reveals that FRB 121102 originates within 100 milliarcseconds of a faint 180-microJansky persistent radio source with a continuum spectrum that is consistent with non-thermal emission, and a faint (twenty-fifth magnitude) optical counterpart. The flux density of the persistent radio source varies by around ten per cent on day timescales, and very long baseline radio interferometry yields an angular size of less than 1.7 milliarcseconds. Our observations are inconsistent with the fast radio burst having a Galactic origin or its source being located within a prominent star-forming galaxy. Instead, the source appears to be co-located with a low-luminosity active galactic nucleus or a previously unknown type of extragalactic source. Localization and identification of a host or counterpart has been essential to understanding the origins and physics of other kinds of transient events, including gamma-ray bursts and tidal disruption events. However, if other fast radio bursts have similarly faint radio and optical counterparts, our findings imply that direct subarcsecond localizations may be the only way to provide reliable associations.

Astronomy: Radio burst caught red-handed

5 January 2017 - 9:23am

Astronomy: Radio burst caught red-handed

Nature 541, 7635 (2017). doi:10.1038/541032a

Authors: Heino Falcke

For almost a decade, astronomers have observed intense bursts of radio waves from the distant cosmos whose origins were unknown. The source of one such burst has now been identified, but this has only deepened the mystery. See Letter p.58

Publishing: A brief history of Stephen Hawking's blockbuster

5 January 2017 - 9:22am

Publishing: A brief history of Stephen Hawking's blockbuster

Nature 541, 7635 (2017). doi:10.1038/nature16881

Author: Elizabeth Leane

Elizabeth Leane surveys the extraordinary influence of the physicist's first foray into popular-science publishing.

Cosmic radio bursts tracked to home galaxy for first time

5 January 2017 - 9:21am

One repeating example of a fast radio burst has finally been pinned down to a tiny and distant dwarf galaxy, narrowing down its precise origin

Metal asteroid and Trojans selected for next NASA missions

5 January 2017 - 9:20am

The US space agency will send probes to metallic asteroid Psyche and the mysterious Trojans that flank Jupiter in the 2020s

NASA Selects Two Missions to Explore the Early Solar System

5 January 2017 - 9:19am
NASA has selected two missions that have the potential to open new windows on one of the earliest eras in the history of our solar system – a time less than 10 million years after the birth of our sun. The missions, known as Lucy and Psyche, were chosen from five finalists and will proceed to mission formulation.

Hidden Secrets of Orion’s Clouds

5 January 2017 - 9:18am
This spectacular new image is one of the largest near-infrared high-resolution mosaics of the Orion A molecular cloud, the nearest known massive star factory, lying about 1350 light-years from Earth. It was taken using the VISTA infrared survey telescope at ESO’s Paranal Observatory in northern Chile and reveals many young stars and other objects normally buried deep inside the dusty clouds.

Mystery cosmic radio bursts pinpointed

5 January 2017 - 9:17am

Astronomers have pinpointed the source of mysterious radio bursts from space.

NASA Selects Mission to Study Black Holes, Cosmic X-ray Mysteries

4 January 2017 - 9:11am
Portal origin URL: NASA Selects Mission to Study Black Holes, Cosmic X-ray Mysteries Portal origin nid: 395700Published: Tuesday, January 3, 2017 - 16:54Featured (stick to top of list): noPortal text teaser: NASA has selected a science mission that will allow astronomers to explore, for the first time, the hidden details of some of the most extreme and exotic astronomical objects, such as stellar and supermassive black holes, neutron stars and pulsars. Objects such as black holes can heat surrounding gases to more than a million degrees. The high-energy X-ray radiation from this gas can be polarized – vibrating in a particular direction. The Imaging X-ray Polarimetry Explorer (IXPE) mission will fly three space telescopes with cameras capable of measuring the polarization of these cosmic X-rays, allowing scientists to answer fundamental questions about these turbulent and extreme environments where gravitational, electric and magnetic fields are at their limits.  “We cannot directly image what’s going on near objects like black holes and neutron stars, but studying the polarization of X-rays emitted from their surrounding environments reveals the physics of these enigmatic objects,” said Paul Hertz, astrophysics division director for the Science Mission Directorate at NASA Headquarters in Washington. “NASA has a great history of launching observatories in the Astrophysics Explorers Program with new and unique observational capabilities. IXPE will open a new window on the universe for astronomers to peer through. Today, we can only guess what we will find.” NASA's Astrophysics Explorers Program requested proposals for new missions in September 2014. Fourteen proposals were submitted, and three mission concepts were selected for additional review by a panel of agency and external scientists. NASA determined the IXPE proposal provided the best science potential and most feasible development plan. The mission, slated for launch in 2020, will cost $188 million. This figure includes the cost of the launch vehicle and post-launch operations and data analysis. Principal Investigator Martin Weisskopf of NASA’s Marshall Space Flight Center in Huntsville, Alabama, will lead the mission. Ball Aerospace in Broomfield, Colorado, will provide the spacecraft and mission integration. The Italian Space Agency will contribute the polarization sensitive X-ray detectors, which were developed in Italy. NASA's Explorers Program provides frequent, low-cost access to space using principal investigator-led space science investigations relevant to the agency’s astrophysics and heliophysics programs. The program has launched more than 90 missions, including Explorer 1 in 1958, which discovered the Van Allen radiation belts around the Earth, and the Cosmic Background Explorer mission, which led to a Nobel Prize. NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages the Explorers Program for the agency's Science Mission Directorate. For more information about the Explorers program, visit: http://explorers.gsfc.nasa.gov For information about NASA, visit: http://www.nasa.gov -end-Portal image: NASA Selects Mission to Study Black Holes, Cosmic X-ray Mysteries Science Categories: Universe

NASA Selects Mission to Study Black Holes, Cosmic X-ray Mysteries

4 January 2017 - 9:10am
NASA has selected a science mission that will allow astronomers to explore, for the first time, the hidden details of some of the most extreme and exotic astronomical objects, such as stellar and supermassive black holes, neutron stars and pulsars.

NASA's Hubble Observations Suggest Underground Ocean on Jupiter's Largest Moon

4 January 2017 - 9:09am

Nearly 500 million miles from the Sun lies a moon orbiting Jupiter that is slightly larger than the planet Mercury and may contain more water than all of Earth's oceans. Temperatures are so cold, though, that water on the surface freezes as hard as rock and the ocean lies roughly 100 miles below the crust. Nevertheless, where there is water there could be life as we know it. Identifying liquid water on other worlds — big or small — is crucial in the search for habitable planets beyond Earth. Though the presence of an ocean on Ganymede has been long predicted based on theoretical models, NASA's Hubble Space Telescope found the best evidence for it. Hubble was used to watch aurorae glowing above the moon's icy surface. The aurorae are tied to the moon's magnetic field, which descends right down to the core of Ganymede. A saline ocean would influence the dynamics of the magnetic field as it interacts with Jupiter's own immense magnetic field, which engulfs Ganymede. Because telescopes can't look inside planets or moons, tracing the magnetic field through aurorae is a unique way to probe the interior of another world.

Join Hubble astronomers during a live Hubble Hangout discussion about Ganymede at 3pm EDT on Thurs., March 12, to learn even more. Visit http://hbbl.us/y6f .

New Year's Fireworks from a Shattered Comet

3 January 2017 - 9:07am
Video Length: 4:07

Earth will pass through a stream of debris from comet 2003 EH1 on January 3, 2017, producing a shower of meteors known as the Quadrantids.

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