Abstract
On a summer day in 2017, astronomers around the world received a message about an exciting collision of two stars far, far away. The message was sent by a team of astronomers from the LIGO and Virgo observatories. These new observatories are very different from the telescopes we have used to study our Universe up until now. LIGO and Virgo are gravitational wave observatories, listening for quiet ripples in spacetime created by the collisions of distant black holes and neutron stars. On August 17, 2017 LIGO and Virgo detected a signal that astronomers named GW170817, from the collision of two neutron stars. Less than two seconds later, NASA's Fermi satellite caught a signal, known as a gamma-ray burst, and within minutes, telescopes around the world began searching the sky. Telescopes in South America found the location of the collision in a distant galaxy known as NGC 4993. For the weeks and months that followed, astronomers watched the galaxy and the fading light from the collision. This is a new kind of multi-messenger astronomy where, for the first time, the same event was observed by both gravitational waves and light.
Highlights
Astronomers around the world received a message about an exciting collision of two stars far, far away
LIGO and Virgo are gravitational wave observatories, listening for quiet ripples in spacetime created by the collisions of distant black holes and neutron stars
For the weeks and months that followed, astronomers watched the galaxy and the fading light from the collision. This is a new kind of multi-messenger astronomy where, for the first time, the same event was observed by both gravitational waves and light
Summary
The stars in the night sky may seem like they have been there forever, but each star was created from gas and dust in space pulled together by gravity. Small- and medium-size stars like our own Sun end their lives as white dwarf stars, the glowing remains of the star’s core. The remains of a supernova explosion is a dense, dark core, either a neutron star or a black hole. X-rays were detected from a distant neutron star and later the same year, the first radio pulsar was discovered. A pulsar is a highly magnetized neutron star that is spinning, sending a beam of radio pulse toward the Earth with each spin. Radio telescopes here on Earth can watch these pulses, which arrive like a steady ticking clock. When scientists planned to build the new LIGO and Virgo gravitational wave detectors, they hoped to find gravitational wave signals from some of these binary neutron star systems (Figure )
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
