What is between the galaxies?

15 thousand galaxies in the lens of the Hubble telescope

Everything astronomers know about it is known through observation. Peering into the depths of space, the space telescope sends to our planet pictures of distant stars, planets and galaxies. Scientists estimate only the observable Universe there are about two trillion galaxies. It's hard to imagine, but thanks to photos we have about them and their location some idea. The astronomer Edwin Hubble in 1925 identified several types : elliptical, irregular, normal spiral, irregular spiral and lenticular. Turns out scientists know what are galaxies and what happens inside them, but do they know what lies between the galaxies?

What is a galaxy?

For example, the milky Way let's see what are the galaxy. So, the galaxy — this is a huge gravitationally bound system. It contains about 200 billion stars, and nebulae, dark matter, planets, clouds of gas and dust and star clusters. All objects in the galaxy, participate in movement about a common center of mass. In the heart of the galaxy is a supermassive black hole, which, by the way, according to scientists .

it looks like the center of the milky Way

Depending on the species, according to the classification Edwin Hubble that every galaxy has its own characteristics. So, the milky Way in its form in a profile remotely similar to a flying saucer. Not so long ago, scientists learned that our galaxy is not flat as previously thought — it turned out that the milky Way is more like a harmonica, as the galaxy as if crushed closer to the edges.

The Distance between galaxies is extremely large. So, the nearest galaxy Andromeda is 2.5 million light years from Earth. Such a distance is hard to imagine. But what is in between galaxies?

Another mystery of the Universe

was filled with gas, mostly hydrogen. Over time, here and there, gravity is pulling the gas towards the clouds, which later turned into a galaxy in which the stars were born. Know why stars Shine? All the matter in the thermonuclear burning of the hydrogen — those stars that become supernovae and die after the explosion “push” the gas back out of galaxies.

There, in a mysterious intergalactic space, the gas is cooled and becomes denser. There he is, while the force of gravity pulls it back to the galaxy where new stars are formed. The process is repeated: gravity condenses the gas into galaxies and stars, the stars explode and emit gas, gravity again pulls the gas and new stars are born.

Hubble Telescope took a picture of a supernova explosion

Over time, in any galaxy starts to run out of the processed gas. And without gas in the Universe can form new stars; live your life and die, and in the end, the galaxy is dying, too. Galaxy live in so-called gas bath, the environment from which they were born, which nourishes them. Galaxy inhale and exhale the gas, and the stars continue to burn until the gas will disappear. Sounds nice, isn't it?

what is the universe?

Previously, the problem with the verification of this theory was the fact that the instruments of the astronomers were barely able to detect signs of intergalactic gas, not to mention his appearance and disappearance. Today, however, thanks to more sensitive instruments, scientists know a lot more. The data indicates that the intergalactic medium rich gas that fills the Universe and gives rise to galaxies. A little less convincing, and sometimes enigmatic evidence about galactic environment show that galaxies live at the expense of recirculation of gas to stars and from stars.

But evidence that the galaxies run out of gas, and stars will cease to be born, which will lead to the destruction of the galaxy so far only preliminary. The fact that even in the young Universe, the gas is not homogeneous. The intergalactic medium is also not pure hydrogen: it is partially filled with elements heavier than hydrogen that are present when stars explode and die.

And yet, despite the many questions scientists agree that this ancient, cooling, a fully ionized intergalactic medium is a well-understood entity, which contains a compelling picture of when and from what there was of the galaxy.

However, despite the emergence of new tools and collaboration of scientists, today the overall picture of birth, life and death of galaxies there. To better understand this, scientists are turning to computer simulations — recently . Regardless, the simulation of real or no, with their help, scientists will be able to get answers to questions about the nature of the intergalactic gas. The fact that simulations — the clearest visualization of how the gas could create a galaxy.

Scientists believe that today, 13.8 billion years after the Big Bang, only 60% of the gas is concentrated in the intergalactic medium; the rest is near the galactic environment and withingalaxies. It turns out that in the vast Universe of galaxies strung in the void, like a lit motorway. Beautiful! Despite the fact that much remains a mystery.