An extraordinarily bright explosion detected in an unexpected place by NASA's Hubble Space Telescope has scientists confused. According to a statement by the US Space Agency, the bright flash of blue light appeared in the middle of seemingly empty space and is thought to have burned at about 36,000 degrees Fahrenheit. NASA explained that this rare explosion is known as 'Luminous Fast Blue Optical Transient (LFBOT)' - a phenomenon which is among the brightest and most unpredictable known visible-light events in the universe.
"'The discovery poses many more questions than it answers.' A Luminous Fast Blue Optical Transient is an intense burst that shines in blue light and evolves rapidly. Hubble pinpointed the location of one, but it confounded astronomers," NASA Hubble wrote on X (formerly Twitter).
"The LFBOT appeared far between two galaxies - far away from any host galaxy. Previous LFBOTs have been found in star-forming regions in the spiral arms of galaxies, so scientists aren't yet sure what astronomical event might trigger an LFBOT far outside of a galaxy," it added.
According to NASA's blog, these cosmic explosions were first discovered in 2018, and only a handful have been found since then. Their origins are poorly understood, but a number of potential explanations have been proposed. Presently, LFBOTs are detected once per year, the space agency said.
The latest LFBOT, nicknamed 'Finch' was detected on April 10, 2023, by the Zwicky Transient Facility, a wide-angle, ground-based camera that scans the entire northern sky every two days. It has left scientists puzzled as it appeared where it wasn't expected to be found, far away from any host galaxy. NASA's Hubble Space Telescope pinpointed its exact location - about 50,000 light years from a nearby spiral galaxy and roughly 15,000 light years from a smaller galaxy.
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"It shined intensely in blue light and evolved rapidly, reaching peak brightness and fading again in a matter of days, unlike supernovae, which take weeks or months to dim," NASA wrote in its blog, adding, "But unlike any other LFBOT seen before, Hubble found that the Finch is located between two neighboring galaxies".
"The Hubble observations were really the crucial thing. They made us realize that this was unusual compared to the other ones like that, because without the Hubble data we would not have known," said Ashley Chrimes, a European Space Agency research fellow.
NASA scientists explained a few hypotheses for what could cause the bright blue flashes. One explanation is that they represent a rare type of supernova known as core-collapse supernovae. The kinds of stars that produce supernovae are found in the spiral arms of galaxies where star birth occurs. All previous LFBOTs have been found in these spiral arms. But the Finch was spotted in intergalactic space, on the outskirts of two galaxies, challenging this theory of the origin of LFBOTs.
"The discovery poses many more questions than it answers," said Mr Chrimes. "More work is needed to figure out which of the many possible explanations is the right one," he added.
