Black Hole Research Frontline June 23, 12:17

Have you ever seen the "Milky Way"?

As you look up at the sky on a sunny, dark night without the moon and your eyes gradually get used to it, you will see a band of faint light.

This time, we will approach the mysterious celestial body "Black Hole" hidden in the Milky Way.

Questions even in junior high school entrance exams

What is the Milky Way in the first place?

And do you know why it looks like a river?

The junior high school entrance exam also asks about the Milky Way.

Problem

The Milky Way looks at the center of the galaxy, but why does it look like a river that crosses the entire sky?

(Renamed 2020 at Winchester Shoei Girls' Academy)

We will look at the answers while adding explanations about the "galaxy" that appears in the problem statement.

The "Galaxy" is a collection of hundreds of billions of stars and other celestial bodies.

It has a flat disk shape with many stars densely packed in the center and shines brightly.

The Earth we live in is also in the galaxy, far from the center, towards the edge.

In fact, the center of the galaxy is the true identity of the Milky Way.

Looking at the brightly shining center from the edge of a galaxy on Earth, it looks like a thin river is flowing in the sky because of the flat shape of the galaxy.

So, the answer to the question is "because we are looking at the central part of the galaxy where the stars are dense from the inside of the galaxy".

Successful shooting of the "contour" of a black hole!

It may seem surprising because the stars are densely packed in the center of the galaxy and it shines brightly, but in the middle is the mysterious celestial body "black hole" that appears in science fiction movies and novels. ..

In May 2022, an international astronomy research group announced that it had successfully photographed the "contour" of a black hole in the center of the galaxy.

The published image shows an orange donut-shaped ring.

According to the research group, the inner part of the ring is the outline of the black hole, and the orange part is the light emitted from the hot gas floating around.

But why did you shoot the "contour"?

Black hole that cannot be seen directly

We talked to a member of an international research group who photographed the outline of a black hole.

This is Mareki Honma, a professor at the Mizusawa VLBI Observatory of the National Astronomical Observatory.

Mr. Homma

"The correct way to say that a black hole is hidden in a hole in a donut-shaped ring. A black hole is a celestial body that sucks in anything, whether it is matter or light, and never let it go out. For this reason, black holes are celestial bodies that can only be seen in total darkness and cannot be seen directly. "

In other words, Mr. Homma and his colleagues captured the light emitted from the gas floating around the black hole, and photographed the outline of the black hole, which was originally invisible.

Mr. Homma

"It can be said that there is no doubt that black holes will definitely exist due to the success of shooting."

Black hole research that began with prophecy

Research on black holes began more than 100 years ago.

It all started when the existence of a black hole was predicted based on the "general theory of relativity" published by the famous physicist Einstein.

After that, with the development of observation equipment, the existence of black holes has been proved not only theoretically but also through actual observations.

However, I haven't been able to see black holes for a long time.

In addition to not emitting light, it was so far away that it looked too small from Earth.

Shooting is possible with international cooperation

One of the telescopes for observing celestial bodies is the radio telescope.

You can observe and visualize the faint radio waves emitted by celestial bodies.

However, even one of the high-performance radio telescopes is not enough for observing black holes.

Therefore, the research group realized the performance of a giant earth-sized telescope by connecting a total of six radio telescopes in Chile, Hawaii, the South Pole, Arizona, Spain, and Mexico.

Homma and his colleagues developed their own program to create images based on the huge amount of data obtained from six radio telescopes, and led to successful shooting.

Mr. Homma

"The moment we succeeded in shooting, we were all happy and happy that we did it. We drank delicious sake that day."

What is the significance of black hole research?

The appearance of a galaxy black hole that I could see for the first time.

Mr. Homma says that research on black holes may lead to understanding the history of the universe, including us human beings.

Mr. Homma

"Some people think that when a galaxy was formed at the beginning of the universe, the first black hole became a so-called" seed "and collected the surrounding gas and played a role. The flow is that the galaxy was formed, the sun and the earth were formed, and life was born. Black holes may have played an important role in such a flow for a while. In that sense, humankind's It may be said that it is such a celestial body that is indirectly related to its existence. "

According to Mr. Homma, a black hole is a "sphere" rather than a "hole", although it has the name "hole".

However, even if I reached out, I couldn't touch it because the space was a sphere.

How can you imagine?

A black hole with many mysteries.

Will the day when the whole picture will be elucidated come someday?

In "Migake, Curiosity!" Of "Weekly Maru-Knowledge News" (broadcast at 8:25 am on Sunday), we will delve into the news every week on the subject of current affairs given in the entrance examination.

Let's think of "why?", In fact, "in the first place" that you want to know as a Kamakura caster.

You can also review the past on the homepage of the corner.

Please take a look from the link below.

https://www3.nhk.or.jp/news/special/maruwaka-migake/