Credit: NASA/JPL-Caltech (Infrared)
Wrapped in a golden blanket, perched high above Earth, AstroSat has a good view of Earth. The space observatory’s five gizmos could keep tabs on the planet, but India has already built the satellites necessary for watching our atmospheric whims. AstroSat has its five eyes blinking at something else entirely, and that’s cosmic chaos.
Whether celestial bodies look like gritty glowing orbs or hued ethereal landscapes depends on the tools used to see them. Light is classified into wavelengths, and different telescopic eyes see different ranges. The Chandra X-Ray Observatory, for instance, sees in X-rays as well as the visible spectrum. In the mottled rainbow image from Chandra above, the X-rays from the neutron star system pop as red, green and blue, and the optical wavelengths show up as gold.
Neutron stars are the shredded remains of giant stars that have died in supernovas, leaving a collapsed core. They’re so dense that one teaspoon could weigh billions of tons, and they generate some of the strongest magnetic fields known in the universe–up to a quadrillion times the strength of Earth’s. Tumultuous bodies such as very hot stars, neutron stars, and black holes attract AstroSat’s attention because of the high energy they emit, and as the Indian Space Research Organization (ISRO)’s first multi-wavelength satellite, its instruments crave ultraviolet (UV) and X-rays.
At 650 km above Earth (that’s a little over 400 miles), AstroSat orbits the Earth once every hour and a half. AstroSat’s high vantage point above the Earth allows to see above our atmosphere, which absorbs high-energy light like a giant sponge-y blanket. AstroSat can see further and fainter events, like star births and other high-energy processes, like those of binary star systems.
Credit: NASA/ESA/Felix Miracle (French Atomic Energy Commission and Institute for Astronomy and Space Physics/Conicet of Argentina)
Launched September of last year, AstroSat has circled our planet more than 5,400 times and observed over 140 cosmic sources. Amid the space anarchy, the satellite has observed the Crab Nebula, the brightest hard X-ray source in the sky. (X-rays are further divided into soft and hard categories, which is just another way of saying X-rays with higher and lower energy.) The mission’s peepers will blink for at least another four years, surveying the skies for more X-ray prey.