A New Way to Look at the Milky Way
2023-07-06
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1For many years, humans have looked up at the collection of stars and planets shining in the night sky that make up the Milky Way.
2However, the Milky Way is now being observed for the first time in a new way.
3Scientists said recently that they have produced an image of the Milky Way not based on light.
4Instead, the image is based on subatomic particles called neutrinos.
5Scientists discovered the high-energy neutrinos in ice deep below Antarctica's surface.
6They then traced their source back to locations in the Milky Way.
7It is the first time these particles have been observed arising from our galaxy.
8This observation of the galaxy is different from what can be seen with our own eyes, or even instruments that measure other electromagnetic sources like radio waves, microwaves, or X-rays.
9The image does not contain stars or planets or other things observable because of their light.
10Rather they are observable because of the neutrinos originating in the galaxy.
11The neutrinos may be from explosive star deaths called supernovas.
12The neutrinos were discovered over a period of 10 years at the IceCube Neutrino Observatory.
13It is part of a U.S. scientific research station at the South Pole.
14The researchers used more than 5,000 sensors covering an area the size of a small mountain.
15"This observation is groundbreaking. It established the galaxy as a neutrino source.
16Every future work will refer to this observation," said Georgia Tech physicist Ignacio Taboada.
17He is the spokesperson for the IceCube research.
18Neutrinos are electrically neutral.
19They are not affected by even the strongest magnetic field and rarely interact with matter.
20That is why they are also called the "ghost particle."
21As neutrinos travel through space, they pass clear through matter like stars, planets, and even people.
22"Just as light goes without stopping through glass, neutrinos can go through everything, including the whole planet Earth," Taboada said.
23Naoko Kurahashi Neilson is a physicist at Drexel University in Philadelphia.
24She is a member of the research team that published its findings in the publication Science.
25Neilson said neutrinos are elementary particles, meaning they are not made up of anything smaller.
26"They are not the building blocks of stuff, like electrons and quarks are, but they are created in nuclear processes," she said.
27Many parts of the universe are impossible to observe using light alone.
28The ability to use particles like neutrinos in astronomy makes for a more complete examination.
29Neutrinos are produced by the same sources as cosmic rays, the highest-energy particles ever observed.
30But cosmic rays, as electrically charged particles, cannot be traced directly back to their source.
31Strong magnetic fields in space change their path.
32But the direction from which neutrinos arrive points directly to their original source.
33The researchers used machine learning to help determine which neutrinos originated in our galaxy and which originated elsewhere.
34How the neutrinos originated is up for debate.
35"This is now the key question," said IceCube lead scientist Francis Halzen.
36"Neutrinos only originate in sources where cosmic rays are produced ...The key question is where these cosmic rays originate," Halzen said.
37"The most likely source of neutrinos and cosmic rays in our galaxy, are the remains of past supernova explosions," Taboada added.
38"But this is unproven so far."
39I'm Dan Novak.
1For many years, humans have looked up at the collection of stars and planets shining in the night sky that make up the Milky Way. However, the Milky Way is now being observed for the first time in a new way. 2Scientists said recently that they have produced an image of the Milky Way not based on light. Instead, the image is based on subatomic particles called neutrinos. 3Scientists discovered the high-energy neutrinos in ice deep below Antarctica's surface. They then traced their source back to locations in the Milky Way. It is the first time these particles have been observed arising from our galaxy. 4This observation of the galaxy is different from what can be seen with our own eyes, or even instruments that measure other electromagnetic sources like radio waves, microwaves, or X-rays. 5The image does not contain stars or planets or other things observable because of their light. Rather they are observable because of the neutrinos originating in the galaxy. The neutrinos may be from explosive star deaths called supernovas. 6The neutrinos were discovered over a period of 10 years at the IceCube Neutrino Observatory. It is part of a U.S. scientific research station at the South Pole. The researchers used more than 5,000 sensors covering an area the size of a small mountain. 7"This observation is groundbreaking. It established the galaxy as a neutrino source. Every future work will refer to this observation," said Georgia Tech physicist Ignacio Taboada. He is the spokesperson for the IceCube research. 8Neutrinos are electrically neutral. They are not affected by even the strongest magnetic field and rarely interact with matter. That is why they are also called the "ghost particle." As neutrinos travel through space, they pass clear through matter like stars, planets, and even people. 9"Just as light goes without stopping through glass, neutrinos can go through everything, including the whole planet Earth," Taboada said. 10Naoko Kurahashi Neilson is a physicist at Drexel University in Philadelphia. She is a member of the research team that published its findings in the publication Science. Neilson said neutrinos are elementary particles, meaning they are not made up of anything smaller. 11"They are not the building blocks of stuff, like electrons and quarks are, but they are created in nuclear processes," she said. 12Many parts of the universe are impossible to observe using light alone. The ability to use particles like neutrinos in astronomy makes for a more complete examination. 13Neutrinos are produced by the same sources as cosmic rays, the highest-energy particles ever observed. But cosmic rays, as electrically charged particles, cannot be traced directly back to their source. Strong magnetic fields in space change their path. But the direction from which neutrinos arrive points directly to their original source. 14The researchers used machine learning to help determine which neutrinos originated in our galaxy and which originated elsewhere. 15How the neutrinos originated is up for debate. 16"This is now the key question," said IceCube lead scientist Francis Halzen. "Neutrinos only originate in sources where cosmic rays are produced ...The key question is where these cosmic rays originate," Halzen said. 17"The most likely source of neutrinos and cosmic rays in our galaxy, are the remains of past supernova explosions," Taboada added. "But this is unproven so far." 18I'm Dan Novak. 19Dan Novak adapted this story for VOA Learning English based on reporting by Reuters. 20__________________________________________________________________ 21Words in This Story 22trace - v. to follow the path or line of 23source - n. the cause of something 24galaxy - n. any one of the very large groups of stars that make up the universe 25originate - v. to begin to exist 26groundbreaking - adj. introducing new ideas or methods 27neutral - adj. not having an electrical charge 28stuff - n. a group or pile of things that are not specifically described 29quark - n. any one of several types of very small particles that make up matter 30key - adj. extremely important