Dancing Black Holes Destined to Merge Emit Weird Light Signal

A collision triggering a titanic release of energy with the power of 100 million supernovae

This simulation helps explain an odd light signal thought to be coming from a close-knit pair of merging black holes, PG 1302-102, located 3.5 billion light-years away. Credits: Columbia University
This simulation helps explain an odd light signal thought to be coming from a close-knit pair of merging black holes, PG 1302-102, located 3.5 billion light-years away.
Credits: Columbia University

Space news (February 07, 2016) – A weird, odd light, 3.5 billion light-years away, called PG 1302-102 –

Astronomers working with NASA’s Hubble Space Telescope and Galaxy Evolution Explorer (GALEX) believe they have the most compelling data yet for the existence of merging black holes. Two black holes astronomers think are in the act of merging called PG 1302-102, appear to be emitting a strange, cyclical light signal. 

NASA's GALEX spacecraft scans the night sky. Credit: JPL/NASA
NASA’s GALEX spacecraft scans the night sky.
Credit: JPL/NASA

Trapped within their combined gravity well at a distance slightly bigger than our solar system, they’re destined to collide in less than a million years and trigger a titanic blast that will be heard across the universe. 

Astronomers first identified PG 1302-102 early this year as one of a number of candidate black hole pairs after they detected a weird light signal emanating from the center of a galaxy. After study and thought scientists demonstrated the varying signal detected is probably produced by the movement of two black holes orbiting each other every five years.

Black holes don’t emit light, but the material surrounding a black hole can. Astronomers used ultraviolet data to track the changing light patterns of PG 1302-102 during the past two decades to make this demonstration. 

We were lucky to have GALEX data to look through,” said co-author David Schiminovich of Columbia University in New York. “We went back into the GALEX archives and found that the object just happened to have been observed six times.”

Astronomers were able to test their prediction that black holes generate a cyclical light pattern. In the case of PG, 1302-102 scientists think one of the pairs of black holes emits more light, which means it’s devouring more material than its partner. During a five-year orbit of one pair of black holes, the light they emit changes and brightens to maximum when it points toward us.

It’s as if a 60-Watt light bulb suddenly appears to be 100 Watts,” explained Daniel D’Orazio, lead author of the study from Columbia University. “As the black hole light speeds away from us, it appears as a dimmer 20-Watt bulb.”

Astronomers call this a relativistic boosting effect, which has previously been detected using visible light. This pair of black holes is traveling toward us at speeds considered relativistic, with the fastest traveling at nearly seven percent the speed of light. 

At this speed, light is squeezed to shorter wavelengths as it travels toward us, in the same way, a train’s whistle squeals at higher frequencies as it comes towards you. This boosts and brightens the light detected, producing the periodic brightening and dimming observed.

D’Orazio, Schiminovich, and colleagues modeled the way it should look in ultraviolet light based on research done by other scientists in visible light. They calculated that if the previous brightening and dimming were due to the relativistic boosting effect as was seen in visible light? It should be detected at ultraviolet wavelengths but amplified about 2.5 times. After checking, they discovered their prediction matched ultraviolet light data provided by the Hubble Space Telescope and GALEX. 

We are strengthening our ideas of what’s going on in this system and starting to understand it better,” said Zoltán Haiman, a co-author from Columbia University who conceived the project.

Astronomers will now use the theories and ideas they develop through the study of PG 1302-102 to help understand merging black holes better and find more binary black hole pairs to observe. 

Once astronomers add the data they collect on merging black holes using the Hubble Space Telescope, GALEX and other observatories to the data they expect to achieve through the study and observation of gravitational waves. It will give us a better idea of the population of merging black holes across the universe and lift the veil on cosmic secrets sure to delight the soul.

Cosmic delights await!

You can learn more about the Hubble Space Telescope here.

Discover GALEX here.

Learn more about black holes here.

Learn more about the present theory on binary black holes here.

Read about astronomers stunning observations of gravitational waves.

Find out what astronomers believe hides beneath the icy shell of Saturn’s moon Enceladus.

Discover the secrets NASA’s New Horizons has been telling astronomers about Pluto.

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