An imaginary view of NASA’s Trans-Neptunian Spacecraft New Horizons.What is dimly shining around the sunZodiacWhat is called. Cosmic dust is generated by reflecting sunlight. (Image Credit: Joe Olmsted / STScI)
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NASA on January 14thTrans-Neptunian Spacecraft “New Horizons”Using the observation data of the National Science FoundationA research team led by Tod LauerAnnounced that it has succeeded in a new measurement of the brightness of the universe. New Horizons is known for exploring Pluto and is currently exploring the Kuiper belt beyond Pluto.
How bright do you think the galaxies in the universe are completely absent? Is it completely dark?
In fact, even in such a part, the universe is filled with the light emitted by countless galaxies, so it is very slightly bright.this“Cosmic visible light background radiation”It’s called.
However, its brightness is so faint that it is very difficult to measure.
This does not change not only from the ground but also from space using the Hubble Space Telescope.Because even observations from spaceZodiacal light generated by cosmic dust reflecting the sun’s raysThis is because it gets in the way. A lot of cosmic dust is floating inside the solar system.
ThereforeThe research team focused on the Trans-Neptunian Spacecraft New Horizons. Because New Horizons is far outside the solar system, it is less affected by zodiacal light, and its surroundings are less affected than when it is darkest around the Hubble Space Telescope.10 timesIs also dark.
The research team is like thisWe succeeded in newly measuring the visible light background radiation of the universe by adding corrections such as removing the influence of light generated by the dust floating in the Milky Way galaxy reflecting the star light of the Milky Way galaxy to the observation data of New Horizons. did.
According to NASA, its brightness is “At night, when I was lying in my bedroom, far away from home, with the curtains open, my neighbor, who lived about 1.6km (a mile) away from it, opened the fridge to eat at night. Bright enough for light to come in through the window and reflect off the walls of the bedroomIt is said.
The research team also estimated the number of galaxies in the universe (including galaxies that cannot be observed due to the limits of the observing device) from this measurement result.Then, in this universeHundreds of billions of galaxiesIt turns out that is presumed to exist. By the way, it is thought that our Milky Way galaxy alone contains about 100 billion stars.
I am really amazed at the size of the universe.
Image Credit: Joe Olmsted/STScI
Source: NASA／paper
Sentence / Shigeyuki Totsugi
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