Incredible time-lapse photography reveals skies shimmering with gamma rays

Most of the light flowing through the universe is invisible to the human eye.

The spectrum ranges from long radio waves to short gamma rays, with the visible portion occupying only a small portion in between. But with telescope technology, we are able to peer into other parts of the spectrum and see all the light in the sky.

NASA’s Fermi Gamma-ray Space Telescope is one such instrument. Gamma radiation is the most energetic light in the universe and is produced by energy sources such as supernova remnants, pulsars, quasars and blazar galaxies, which are powered by supermassive black holes whose enormous appetites create Light traveling through time and space.

Gamma radiation is difficult to see from the Earth’s surface because it is blocked by our atmosphere. That’s a good thing because it can be very dangerous, but it does mean we need to get creative about studying it.One solution: If the atmosphere prevents us from observing gamma rays, go somewhere without an atmosphere

Fermi was launched in 2008, and since then it has been making full use of its status to study sources of gamma radiation in the universe. We’ve seen an animation of the gamma-ray sources it saw over the course of the year from February 2022 to February 2023.

Now, NASA scientists have compiled a time-lapse of the actual data collected between August 2008 and August 2022.

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“The first thing that catches your eye in the movie is the steady arc of light on the screen,” said Judy Racusin, an astronomer at NASA’s Goddard Space Flight Center, describing the timelapse in the game. ” That’s our Sun, and its apparent motion reflects the Earth’s annual orbit around it.”

The Sun is a stable source of relatively dim gamma radiation. Scientists believe that it is not emitting gamma radiation from within, but is the result of a constant bombardment of cosmic radiation particles that are always flowing through the universe. When they hit the Sun, their interaction with the Sun’s atmosphere produces gamma radiation.

From time to time, however, the Sun erupts in huge flares that produce X-rays and gamma rays, becoming the brightest thing in the gamma-ray sky for a brief period of time. (Given that the Sun is a star and very close to us, it is usually the brightest object in the sky, with the exception of gamma radiation, as you can see in time-lapse photography.)

Most of the gamma-ray sources seen by Fermi were blazar galaxies. These are distant galaxies with active supermassive black holes. A black hole doesn’t emit light, but it draws nourishment from the huge clouds of dust and gas that billow violently around it.

The cloud itself is very hot and very bright, but the gamma radiation seen by Fermi comes from jets of material that are diverted along magnetic field lines outside the black hole and ejected from the black hole’s poles at extremely fast speeds. A blazar is a galaxy in which one of the jets is pointed directly at us, so it appears much brighter than a jet pointing in another direction.

These jets can flash in brightness, which is one of the things Fermi scientists are watching.

“The Milky Way’s bright, steady gamma-ray glow is punctuated by intense near-light speed jets driven by supermassive black holes at the cores of distant galaxies,” described Seth Digel of the SLAC National Accelerator Laboratory. , days-long flares.” , who created these images.

“These violent eruptions could have appeared anywhere in the sky, occurred millions to billions of years ago, and their light was just reaching Fermi when we observed them.”

Other sources of gamma radiation include supernova remnants such as the Crab Nebula, exploding stars, and pulsars. Due to the way the data is processed, events of shorter duration, such as the gamma-ray bursts of supernovae, do not appear in time-lapse photography.

But don’t worry, they won’t go unnoticed. Every spot of light detected by Fermi is of interest to scientists studying large amounts of data.

The Fermi Project only operates for 5 to 10 years. So far it has runtimes over 15.5 and counting. If we’re lucky, we might discover more, revealing to us the secrets of the most powerful events and objects in the universe.