Fermi Gamma-ray Space Telescope
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What is the Fermi Gamma-ray Space Telescope?
The Fermi Gamma-ray Space Telescope is a United States satellite designed to study gamma ray-emitting sources, such as gamma-ray bursts, pulsars, and high-speed jets emitted by black holes. Launched on June 11, 2008, it carries two instruments, the Large Area Telescope (LAT) and the Gamma-ray Burst Monitor (GBM), operating in the energy range of 10 keV to 300 GeV.
Unlike standard optical telescopes, gamma-ray telescopes detect gamma rays by the optical flashes they produce when interacting with a specially designed instrument. The Fermi telescope discovered pulsars that emitted only gamma rays. It also mapped the entire sky in its first 95 hours of operation.
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Why was the Fermi Gamma-ray Space Telescope launched?
The Fermi Gamma-ray Space Telescope, a United States satellite launched on June 11, 2008, was designed to study gamma ray-emitting sources, which are the universeās most violent and energetic objects. These include gamma-ray bursts, pulsars, and high-speed jets emitted by black holes.
Fermi carries two instruments, the Large Area Telescope (LAT) and the Gamma-ray Burst Monitor (GBM), which work in the energy range of 10 keV to 300 GeV (10,000 to 300,000,000,000 electron volts).
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What kinds of things does the Fermi Telescope observe in space?
The Fermi Gamma-ray Space Telescope is designed to observe the universe's most energetic objects and events. These include gamma-ray bursts, pulsars, and high-speed jets emitted by black holes. Fermi discovered pulsars that emit only gamma rays, with the emission not originating from the poles like radio pulsars, but far from the neutron star's surface.
Fermi has also observed gamma-ray emissions from novae and has contributed to the study of millisecond pulsars. Additionally, it aids in testing theories about the structure of space-time by observing photons of different energies from gamma-ray bursts.
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How does the Fermi Telescope detect gamma rays?
The Fermi Gamma-ray Space Telescope identifies gamma rays using two instruments: the Large Area Telescope (LAT) and the Gamma-ray Burst Monitor (GBM). Because gamma rays can't be focused with lenses or mirrors, the LAT's main detectors are made of silicon and tungsten strips set at right angles. When gamma rays enter the strips, they produce electron-positron pairs that ionize the material. The ionized charge is proportional to the strength of the gamma ray, and the arrangement of the strips helps determine the direction of the incoming radiation. The GBM consists of 12 detectors, each containing a thin single-crystal disk of sodium iodide. When a gamma-ray strikes the crystal, it emits flashes of light that are counted by light-sensitive tubes.
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What are some important discoveries made by the Fermi Telescope?
The Fermi Gamma-ray Space Telescope, launched in 2008, studies the universe's most energetic objects using the Large Area Telescope (LAT) and the Gamma-ray Burst Monitor (GBM).
Important discoveries by Fermi include:
* Identifying the first pulsar that emits only gamma rays within the supernova remnant CTA 1. Unlike radio pulsars, the gamma-ray emissions arise far from the neutron star's surface.
* Detecting the first gamma-ray emission from a nova, which was previously thought to lack the energy to produce gamma rays.
* Limiting the grainy structure of space-time to smaller than about 10^-33 cm by observing photons of different energies from a gamma-ray burst.
* Discovering 17 millisecond pulsars, which are the fastest rotating pulsars.3 Britannica SourcesCreated from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles. -
How has the Fermi Telescope helped scientists better understand the universe?
The Fermi Gamma-ray Space Telescope, launched in 2008, studies the universe's most energetic objects using the Large Area Telescope (LAT) and the Gamma-ray Burst Monitor (GBM). These instruments detect gamma rays, which are unlike visible light and X-rays because they cannot be focused with lenses or mirrors. Instead, the LAT uses silicon and tungsten strips to detect electron-positron pairs produced by gamma rays, while the GBM uses sodium iodide detectors to calculate the location of gamma-ray bursts.
Fermi has notably discovered pulsars seen only in gamma rays within the supernova remnant CTA 1, revealing that their emissions originate far from the neutron star surfaces. It has also increased the number of known millisecond pulsars and, by observing gamma-ray bursts, has helped limit the possible grainy structure of space-time to smaller than 10^-33 cm. In 2010, Fermi detected the first gamma-ray emission from a nova, which was previously thought impossible due to insufficient energy.
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Fermi Gamma-ray Space Telescope, U.S. satellite, launched June 11, 2008, that was designed to study gamma ray-emitting sources. These sources are the universeās most violent and energetic objects and include gamma-ray bursts, pulsars, and high-speed jets emitted by black holes. The National Aeronautics and Space Administration is the lead agency, with contributions by France, Germany, Japan, Italy, and Sweden.
Fermi carries two instruments, the Large Area Telescope (LAT) and the Gamma-ray Burst Monitor (GBM), which work in the energy range of 10 keV to 300 GeV (10,000 to 300,000,000,000 electron volts) and are based on highly successful predecessors that flew on the Compton Gamma Ray Observatory (CGRO) in the 1990s. Unlike visible light or even X-rays, gamma rays cannot be focused with lenses or mirrors. Therefore, the main detectors of the LAT are made of silicon and tungsten strips at right angles to each other. Gamma rays produce electron-positron pairs that then ionize material in the strips. The ionized charge is proportional to the strength of the gamma ray. The arrangement of the strips helps determine the direction of the incoming radiation. Cosmic rays are far more common than gamma rays, but the LAT has materials that interact with cosmic rays only and with both cosmic rays and gamma rays, so cosmic rays can be distinguished and ignored. In its first 95 hours of operation, the LAT produced a map of the entire sky; CGRO took years to produce a similar map.
The GBM consists of 12 identical detectors, each containing a thin single-crystal disk of sodium iodide positioned as a face of an imaginary dodecahedron. An incident gamma ray causes the crystal to emit flashes of light that are counted by light-sensitive tubes. The same flashes may be seen by up to half of the detectors but at different intensities depending on the detectorās angle to the source. This process allows the calculation of a gamma-ray burstās location so that the spacecraft can be oriented to point the LAT at the source for detailed observations.
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In 2008 Fermi discovered within the supernova remnant CTA 1 the first of a population of pulsars that are seen only in gamma rays. The gamma-ray emissions do not come from particle beams at the poles of the pulsars, as is the case with radio pulsars, but instead arise far from the surfaces of the neutron stars. The precise physical process that generates the gamma-ray pulses is unknown. Fermi has also increased the number of known millisecond pulsars (the fastest rotating pulsars, with periods of 1 to 10 milliseconds) by discovering 17 such objects.
In some theories of physics that would unite general relativity, which describes the universe on the largest scales, with quantum mechanics, which describes the universe on the smallest scales, space-time would be quantized into discrete pieces. If space-time had such a structure, photons with higher energies would travel faster than those with lower energies. By observing photons of different energies that originated from a gamma-ray burst 7.3 billion light-years from Earth and arrived at Fermi at the same time, astronomers were able to limit any possible grainy structure of space-time to smaller than about 10ā33 cm.
In 2010 Fermi observed the first gamma-ray emission from a nova. It had been previously thought that novas did not generate enough energy to produce gamma rays.