Time-lapse photographic galaxy

On June 1 day local time, the National Aeronautics and Space Administration (NASA) released a video in official website, showing the process of a supernova from light emission to dimming by time-lapse photography.

It is reported that this supernova, code-named SN 20 18gv, is about 70 million light-years away from the Earth and is located in the spiral galaxy NGC 2525. It was first discovered by Japanese amateur astronomer Hiroichi Sakamoto on 20 18 1.

The video shows that when SN 20 18gv appears at the edge of the Milky Way, the light at the beginning is very bright, far more dazzling than other nearby stars. When a star releases energy equivalent to the energy of the sun for billions of years in a few days, it is known that this is its last amazing moment.

Like the celebrity paparazzi, NASA's Hubble Space Telescope captured the explosion of this supernova. The enlarged spiral galaxy NGC 2525 in the video looks about half of the Milky Way. The spiral galaxy NGC 2525 was discovered by British astronomer William in 179 1 year. Herschel discovered it and later named it? Spiral nebula? .

Hubble did not record the initial explosion before 20 18 1, but it took nearly a year to continuously track and take these photos and assemble them into time-lapse lenses. At the peak of the explosion, the brightness of this star was as high as 5 billion suns, eclipsing the brightest stars in the Milky Way.

Institute of Space Telescope Science Adam? Reese (Nobel Prize winner) and Hopkins University will jointly study the relevant data of this supernova to measure the expansion rate of the universe.

When a supernova reaches its critical mass, its core becomes hot enough to trigger nuclear fusion and turn it into a huge atomic bomb. This time, the explosion turned into a super huge fireball, which gave off the last amazing light and finally cooled down slowly.

Because these supernovae have the same peak brightness, they are called by scientists? Standard candles? , used as a cosmic tape measure. Knowing the actual brightness of a supernova, astronomers can calculate the distance of its main galaxy, which enables astronomers to measure the expansion rate of the universe. In the past 30 years, the information provided by Hubble telescope has greatly improved the accuracy of the expansion rate of the universe.

Supernova is a violent explosion experienced by some stars at the end of their evolution. This kind of explosion is extremely bright, and the sudden electromagnetic radiation in the process can often illuminate the whole galaxy where it is located, and it may last for weeks to months or even years before it gradually decays. During this period, the radiation energy released by supernovae can be equivalent to the total radiation energy of the sun in a lifetime.

A star can disperse most or even almost all the matter by explosion and radiate shock waves to the surrounding interstellar matter. This shock wave will lead to the formation of a shell-like structure composed of expanding gas and dust, which is called supernova remnant.

There are two ways to trigger a supernova: the star suddenly rekindles the fire of nuclear fusion, or the gravitational collapse of the core of a massive star. In the first case, a white dwarf can absorb or merge its companion star, accumulate enough mass, raise the core temperature, then ignite carbon fusion, trigger uncontrolled nuclear fusion and completely destroy the star; In the second case, the core of a massive star may suffer a sudden gravitational collapse, releasing gravitational potential energy and producing a supernova explosion.