Astronomy Now – Page 108

Enceladus’ phantom limb

4 October 2017 Astronomy Now

The brightly lit limb of a crescent Enceladus looks ethereal against the blackness of space. The rest of the moon, lit by light reflected from Saturn, presents a ghostly appearance.

Hubble observes the farthest active inbound comet yet seen

4 October 2017 Astronomy Now

NASA’s Hubble Space Telescope has photographed the farthest active inbound comet ever seen, at a whopping distance of 1.5 billion miles from the Sun. Slightly warmed by the remote Sun, it has already begun to develop an 80,000-mile-wide fuzzy cloud of dust, called a coma, enveloping a tiny, solid nucleus of frozen gas and dust.

Seeing double: Scientists find elusive giant black hole pairs

4 October 2017 Astronomy Now

Astronomers have identified a bumper crop of dual supermassive black holes in the centers of galaxies. This discovery could help astronomers better understand how giant black holes grow and how they may produce the strongest gravitational wave signals in the Universe.

Gravitational waves from a binary black hole merger observed by LIGO and Virgo

27 September 2017 Astronomy Now

The LIGO Scientific Collaboration and the Virgo collaboration report the first joint detection of gravitational waves with both the LIGO and Virgo detectors. This is the fourth announced detection of a binary black hole system and the first significant gravitational-wave signal recorded by the Virgo detector, and highlights the scientific potential of a three-detector network of gravitational-wave detectors.

Highest-energy cosmic rays have extragalactic origin

26 September 2017 Astronomy Now

A 50-year-old debate has at last been settled: the highest-energy cosmic rays do not originate in our own galaxy but in galaxies located tens or even hundreds of millions of light-years away.

Fast radio bursts may be firing off every second

25 September 2017 Astronomy Now

When fast radio bursts, or FRBs, were first detected in 2001, astronomers had never seen anything like them before. Since then, astronomers have found a couple of dozen FRBs, but they still don’t know what causes these rapid and powerful bursts of radio emission.

Comet or asteroid? Hubble discovers that a unique object is a binary

22 September 2017 Astronomy Now

NASA’s Hubble Space Telescope helped an international team of astronomers find that an unusual object in the asteroid belt is, in fact, two asteroids orbiting each other that have comet-like features. These include a bright halo of material, called a coma, and a long tail of dust.

Two stars, three dimensions, and oodles of energy

19 September 2017 Astronomy Now

For decades, astronomers have known about irregular outbursts from the double star system V745 Sco, which is located about 25,000 light-years from Earth. Astronomers were caught by surprise when previous outbursts from this system were seen in 1937 and 1989. When the system erupted on February 6, 2014, however, scientists were ready to observe the event with a suite of telescopes including NASA’s Chandra X-ray Observatory.

NASA’s Curiosity Mars rover climbing toward ridge top

18 September 2017 Astronomy Now

NASA’s Mars rover Curiosity has begun the steep ascent of an iron-oxide-bearing ridge that’s grabbed scientists’ attention since before the car-sized rover’s 2012 landing.

New supernova analysis reframes dark energy debate

18 September 2017 Astronomy Now

The accelerating expansion of the universe may not be real, but could just be an apparent effect, according to new research. The new study finds the fit of Type Ia supernovae to a model universe with no dark energy to be very slightly better than the fit to the standard dark energy model.