This article was originally published in dialogue. The publication contributed this article to Space.com Expert Voices: Columns and Insights.
Amy Lane is an assistant professor of physics at the University of Tampa, where his research interests lie in understanding how the universe began and evolved through the most energetic astrophysical explosions: gamma-ray bursts (GRBs), supernovae, merging neutron stars, and black holes.
When distant stars explode, they emit flashes of energy called gamma ray burst Bright enough that the telescope can be turned back on Earth They can be detected.Study these pulses, which may also come from the merger of some exotic objects, e.g. black hole and Zhongxing, can help astronomers like me Learn about the history of the universe.
Space telescopes detect an average of one gamma-ray burst per day, and thousands of them have been detected over the years, and a community of volunteers is making the study of these bursts possible.
November 20, 2004 NASA release Neil Gales Swift Observatory, also known as Swift. Swift is a multi-wavelength space telescope that scientists are using to learn more about these mysterious gamma-ray flashes. universe.
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Gamma-ray bursts usually last only a short time timefrom seconds to minutes, and most of their emissions are in gamma rays, they are part of the spectrum that our eyes cannot see.Gamma rays contain large amounts of energy and can Damage human tissue and DNA.
Fortunately, Earth’s atmosphere blocks most gamma rays spaceBut that also means the only way to observe gamma-ray bursts is through a space telescope like Swift. Throughout his 19 years of observation, Swift observed Exceed 1,600 gamma-ray bursts. The information it gathers from these bursts can help astronomers on the ground measure the distance to these objects.
look back at past
Data from Swift and other observatories tell astronomers that gamma-ray bursts are among the most powerful explosions in the universe. They are so bright that space telescopes like Swift can detect them throughout the universe.
In fact, gamma-ray bursts are one of The most distant astrophysical object Look through the telescope.
Since light travels at a finite speed, astronomers actually look back at past When they set their sights further into the universe.
The most distant gamma-ray burst ever observed occurred at such a distance that its light took 13 billion years to reach Earth. So when telescopes took pictures of gamma-ray bursts, they were observing events from 13 billion years ago.
Gamma-ray bursts allow astronomers to Understand the history of the universeincluding birth rate and population Star Changes over time.
Types of gamma ray bursts
Astronomers now know that there are essentially Two types of gamma ray bursts – Long and short. They are classified based on pulse duration. Long gamma-ray bursts have pulses longer than two seconds, and at least some of these events are associated with supernovae—exploding stars.
When a massive star, or a star at least eight times the mass of the Sun, runs out of fuel, it explodes into a star. Supernova and collapses into neutron star Or a black hole.
Neutron stars and black holes are both very compact. If the entire Sun were shrunk to about 12 miles in diameter, the size of Manhattan, as dense as a neutron star.
Some particularly large stars also emit streams of light when they explode. These jets are concentrated beams driven by structured magnetic fields and charged particles.As these jets point toward Earth, telescopes like Swift will Detecting gamma ray bursts.
Short gamma-ray bursts, on the other hand, have pulses shorter than two seconds.Astronomers suspect that most of these short bursts occur during either of two events neutron star Or a neutron star and a black hole merge.
When a neutron star gets too close to another neutron star or a black hole, the two objects will orbit each other, getting closer as they lose some energy through gravity waves.
These objects eventually merge and emit short jets. When short jets are pointed toward Earth, space telescopes can detect them as short gamma-ray bursts.
Classification of gamma ray bursts
Classifying a burst as short or long is not always simple. Over the past few years, astronomers have discovered a number of strange short gamma-ray bursts associated with supernovae rather than expected mergers. They also found some long gamma-ray bursts associated with mergers rather than supernovae.
These puzzling cases show that astronomers don’t fully understand how gamma-ray bursts are created. They suggest astronomers need to better understand gamma-ray pulse shapes in order to better connect the pulses to their origins.
However, pulse shape is different from pulse duration, making it difficult to classify systematically. Pulse shapes can be extremely diverse and complex. So far, even machine learning algorithms have not been able to correctly identify all the detailed pulse structures of interest to astronomers.
My colleagues and I enlisted the help of volunteers through NASA to identify the pulse structure. Volunteers learned to identify pulse structures and then viewed and classified the images on their computers.
Our preliminary results show that these volunteers, also known as citizen scientists, can quickly learn and identify the complex structure of gamma-ray pulses. Analyzing this data will help astronomers better understand how these mysterious bursts occur.
Our team wanted to see if more gamma-ray bursts in the sample challenged previous classifications of short and long.We will use this data to more accurately explore the history of the universe Gamma-ray burst observations.
This citizen science project, Explosion Chaserhas been growing since our initial results, and we are actively recruiting new volunteers to join our quest to study the mysterious origins behind these outbreaks.
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