Astronomers discovered a real “tell-tale heart” in space, 6,500 light-years from Earth. The “heart” is the crushed core of a long-dead star, called a neutron star, which exploded as a supernova and is now still beating with rhythmic precision. Evidence of its heartbeat are rapid-fire, lighthouse-like pulses of energy from the fast-spinning neutron star. The stellar relic is embedded in the centre of the Crab Nebula, the expanding, tattered remains of the doomed star. Image credits: NASA and ESA, Acknowledgment: M. Weisskopf/Marshall Space Flight Center.The eerie glow of a dead star, which exploded long ago as a supernova, reveals itself in this NASA Hubble Space Telescope image of the Crab Nebula. But don’t be fooled. The ghoulish-looking object still has a pulse. Buried at its centre is the star’s telltale heart, which beats with rhythmic precision.
The “heart” is the crushed core of the exploded star. Called a neutron star, it has about the same mass as the Sun but is squeezed into an ultra-dense sphere that is only a few miles across and 100 billion times stronger than steel. The tiny powerhouse is the bright star-like object near the centre of the image.
This surviving remnant is a tremendous dynamo, spinning 30 times a second. The wildly whirling object produces a deadly magnetic field that generates an electrifying 1 trillion volts. This energetic activity unleashes wisp-like waves that form an expanding ring, most easily seen to the upper right of the pulsar. The nebula’s hot gas glows in radiation across the electromagnetic spectrum, from radio to X-rays. The Hubble observations were taken in visible light as black-and-white exposures. The Advanced Camera for Surveys made the observations between January and September 2012. The green hue has been added to give the image a Halloween theme.This time-lapse movie of the Crab Nebula, made from NASA Hubble Space Telescope observations, reveals wave-like structures expanding outward from the “heart” of an exploded star. The waves look like ripples in a pond. The heart is the crushed core of the exploded star, or supernova. Called a neutron star, it has about the same mass as the Sun but is squeezed into an ultra-dense sphere that is only a few miles across and 100 billion times stronger than steel. This surviving relic is a tremendous dynamo, spinning 30 times a second. The rapidly spinning neutron star is visible in the image as the bright object just below centre. The bright object to the left of the neutron star is a foreground or background star. The movie is assembled from ten Hubble exposures taken between September and November 2005 by the Advanced Camera for Surveys. Image credits: NASA and ESA, Acknowledgment: J. Hester (Arizona State University).The Crab Nebula is one of the most historic and intensively studied supernova remnants. Observations of the nebula date back to 1054 A.D., when Chinese astronomers first recorded seeing a “guest star” during the daytime for 23 days. The star appeared six times brighter than Venus. Japanese, Arabic, and Native American stargazers also recorded seeing the mystery star. In 1758, while searching for a comet, French astronomer Charles Messier discovered a hazy nebula near the location of the long-vanished supernova. He later added the nebula to his celestial catalogue as “Messier 1,” marking it as a “fake comet.” Nearly a century later British astronomer William Parsons sketched the nebula. Its resemblance to a crustacean led to M1’s other name, the Crab Nebula. In 1928 astronomer Edwin Hubble first proposed associating the Crab Nebula to the Chinese “guest star” of 1054.
The nebula, bright enough to be visible in amateur telescopes, is located 6,500 light-years away in the constellation of Taurus.
In May 2010, a South African amateur astronomer pointed his telescope toward nearby galaxy NGC 300 and discovered what appeared to be a supernova — a massive star ending its life in a blaze of glory. However, SN 2010da is what we call a ‘supernova impostor’ — something initially thought to be a supernova, but later releaved as a massive star showing an enormous flare of activity.
Early on the evening of Wednesday, 23 December, observers in the British Isles can see the 13-day-old waxing gibbous Moon pass in front of first-magnitude Aldebaran — the ‘Eye of the Bull’ in Taurus — the brightest star to be occulted for UK observers in 2015. Here’s our observing guide to this readily observable event in large binoculars and small telescopes.
The December Geminid meteor shower is generally regarded as the richest and most reliable of the major annual shooting star displays. This year the predicted peak occurs close to 12h UT on 14 December, though high rates of activity should be encountered between 8pm GMT on Thursday, 13 December and 5pm GMT the following evening.
