On Monday, Oct. 16, 2017, Astronomers announces that the Laser Interferometer Gravitational-Wave Observatory (LIGO) and the Virgo detector facilities, along with 70 other facilities across the world, had detected gravitational waves from the collision of two neutron stars.
What are neutron stars and why do they collide?
- Neutron stars are the smallest and densest stars known to man formed when their larger counterparts explode in a supernova
- The stars are 12 miles in diameter and 1.1 – 1.6 times the mass of the sun; a teaspoon of neutron star matter would weigh 1 billion tons
- These specific stars, 130 million light years away in the NGC 4993 galaxy, were victims of orbital decay, where their gravitational fields slowly pulled their orbits closer and closer together until collision
Why is this discovery important?
- Previously, gravitational waves have only been seen for black hole collisions
- This event provides astrophysicists will a plethora of new information about the inner workings of these neutron stars, their emissions and how fundamental physics concepts actually play out in space
- Also provided insights into the production of gamma ray bursts, universe expansion rates and the origin of heavy elements like platinum or gold
- The visual discovery of the supernova that caused the waves (named SSS17a) provided scientists with the first look at the debris of neutron star collision ever observed.
Round and round they go – then BOOM! This animation begins with the final moments of two neutron stars (the super-dense cores of exploded massive stars), whirling around each other in a galaxy 130 million light-years away. Gravitational waves (rippling disturbance in space-time, shown here as pale arcs) bleed away orbital energy, causing the stars to move closer together and merge. As the stars collide, this explosive event emits light across a series of different wavelengths – first gamma rays (magenta), then ultraviolet (violet), then visible and infrared (blue-white to red) and once the jet directed toward us expanded into our view from Earth, X-rays (blue). Our Fermi Gamma-Ray Space Telescope witnessed this event on August 17, 2017 and we watched it unfold over multiple days with a variety of other telescopes, including the Swift spacecraft, the Hubble Space Telescope (@NASAHubble), the Spitzer Space Telescope, our Chandra X-Ray Observatory (@NASAChandraXray) and our NuSTAR mission. The detectors at the Laser Interferometer Gravitational-Wave Observatory (LIGO) received a gravitational wave signal just 1.7 seconds before the first light was seen by Fermi, making this the first event observed in both light and gravitational waves. Credit: @NASAGoddard/CI Lab #space #nasa #universe #galaxy #stars #astrophysics #astronomy #science #gammarays #ultraviolet #infrared #xrays #gravitationalwaves #neutronstars #hubble #chandra #spitzer #nustar #fermi #swift