Astronomers detect a magnetic field 16,000 long light years on a distant galaxy when Universe still young!
The 9io9 galaxy’s gravitational lens system emits polarized light as a sign of the presence of a magnetic field. Credit: ALMA (ESO/NAOJ/NRAO)/J. Geach et al.
Light from this distant galaxy travels more than 11 billion years to reach the detectors of the ALMA radio telescope in Chile. If so, this light left the galaxy when the universe was only 2.5 billion years old. And that means, the magnetic field was formed when the universe was young.
Magnetic Field in the Universe
Almost all objects in the universe have a magnetic field. Small objects such as planets and stars generate their own magnetic fields from dynamo activity that is created when rotating streams of electrically charged plasma forces weak magnetic fields to fold away. On a larger scale, astronomers also find magnetic fields in nebulae, supernova remnants, and protoplanetary disks. In such cases a complex flow of charged particles can produce a weak magnetic field.
Galaxies and galaxy clusters also have a magnetic field although the magnetic field is very weak. Only one millionth the strength of Earth’s magnetic field!
But, even though they are weak, the magnetic fields in galaxies and galaxy clusters can stretch for millions of light years. How the magnetic fields in galaxies and galaxy clusters form is still a question. Because to produce a magnetic field, it takes charged particles moving together. However, when the universe was young, or more precisely, before the first generations of stars formed, our universe was neutral. And neutral gas will not be able to produce a magnetic field. Therefore, the universe must have another way of generating a magnetic field.
If the universe has a magnetic field seed, then the magnetic field can experience a strengthening of the evolution of the universe turning neutral gas into electrically charged plasma.
But how the magnetic field seed was formed is still a question and mystery. It is still not clear when and how quickly the magnetic field was first formed in the universe.
News from the Far Galaxy
ALMA radio telescope observations have brought good news from a distant galaxy when the universe was young. Observational data 9io9 discovered in a citizen science project in 2014, shows the existence of a magnetic field!
This distant galaxy 9io9 is a two-galactic gravitational lens system with a redshift of z= 2.6. The galaxies that experience gravitational lensing in this system are at a distance of 11.1 billion light years. To detect this magnetic field, a team of astronomers observed the glow of dust grains from the distant galaxy 9io9.
If a galaxy has a magnetic field, then the dust grains within the galaxy will align themselves and emit polarized light. That means, light oscillates along a certain direction and is not random.
The ALMA radio telescope detects this polarized light coming from 9io9. Even more interesting, the magnetic field in these distant galaxies is fully formed and appears in a structure similar to that of the magnetic fields in nearby galaxies. Even though its magnetic field is 1000 times weaker than Earth’s, the magnetic field in this distant galaxy 9io9 stretches more than 16,000 light years!
This finding indicates that magnetic fields that stretch across galaxies can form quickly when young galaxies are forming. And of course this cannot be separated from the role of intense star formation that occurred when the Universe was young. The star formation accelerates the formation of the magnetic field.
This discovery is inevitably a new window for the study of galaxies, especially with respect to matter for the formation of new stars.
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2023-09-07 02:12:00
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