The solar system is located almost on the outskirts of the Milky Way, in the plane of the galactic disk. It has few neighbors, the interstellar medium is very rarefied, and the nearest exoplanet is more than four light years away. The main stellar population of the Galaxy is concentrated in the core behind a dense curtain of gas and dust, almost thirty thousand light-years from us. It is technically impossible for modern earthlings to overcome such a distance, but the discoveries of astrophysics make it possible to quite reliably describe how such a journey will look like.
Get closer to the speed of light
To reach at least the planetary system closest to us, engines are needed that develop near-light speeds.
American astrophysicist, author of the concept of time travel with the help of wormholes, Kip Thorne in the book “Interstellar. Science Behind the Scenes”describes three engine options. First, it is fusion-powered. A hydrogen bomb detonates inside the hemispherical shield. The shockwave from the explosion pushes the shield and the ship attached to it. So one can develop one-thirtieth the speed of light.
In addition, Thorne offers a system with a laser focused by a giant Fresnel lens onto a 100 km sail. The pressure of a powerful stream of photons accelerates a ship with such a sail to one-fifth the speed of light.
The most fantastic option is to use a system of two rotating black holes with strongly elliptical orbits. If you fly long enough from one to the other in those moments when they move towards each other, you can approach the speed of light.
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Let's say the ship is fast enough, the problems of refueling and radiation safety have been resolved and nothing prevents us from going to the center of the Milky Way in a virtually straight line, focusing on the constellation Sagittarius.
Due to the large distances between objects in space, there is no need to be afraid of collisions, and there is no need to dodge a head-on asteroid, as depicted in science fiction films. As they say, break through.
After Neptune we find ourselves in the Kuiper belt, filled with small stone bodies. Its most famous representative is Pluto, stripped of the title of planet in 2006.
Then we cross the Oort cloud - the theoretically predicted "donut" orbiting on the outskirts of the solar system. No one watched him directly. It is indicated by the trajectories of long-period comets.
“The Oort cloud is an accumulation of frozen bodies. It begins at a distance of about three hundred billion kilometers and can, hypothetically, extend beyond one light-year, says Evgeny Semenko, a senior researcher at the Special Astrophysical Observatory of the Russian Academy of Sciences, to RIA Novosti.
When the gravitational force of the Sun weakens so much that it can be ignored against the background of gravity of other stars, we will leave the limits of our system and go out into interstellar space. This will happen after about two years of flying at the speed of light.
Anatomy of the Milky Way.
In the open ocean
Our galaxy can be thought of as a ball with several rays. If you spin it, then the rays will wrap around in the form of spirals - astronomers call them arms. There are at least four of them, and maybe seven - it is impossible to say more precisely yet. The solar system is located in the northern galactic hemisphere, in the Orion arm, 80-90 light years above the equatorial plane.
The bulk of the stars, gas and dust of the Galaxy is concentrated in the plane, therefore, looking from the Earth in the direction of its center, we see a whitish river in the night sky. Hence the name - Milky Way. The galactic core itself is inaccessible for observation in the optical range.
“The absorption of light by dust and gas is so high that, strictly speaking, one photon in ten billion reaches us from the center of the Galaxy. If we could remove dust from the plane, then the central part would shine in the sky like a full moon,”explains Semenko.
The exception, according to him, are "windows" - the intervals of the inner arms of the Galaxy, through which separate regions shine through, where the absorption of light is much less.
Dust and gas are transparent to infrared radiation and radio waves, so astronomers work in these ranges, studying the central parts of the galaxy and everything beyond them.
Clouds of gas and dust are the remnants of stars and matter from extragalactic space. Sometimes they form bubbles blown up by the stellar wind. If the gas is strongly crushed during the birth of a star, point radio sources - masers - appear in it.
“Nebulae heated by very hot stars are a very beautiful sight. In areas with massive stars, we will feel a powerful stellar wind,”says the scientist.
The first object outside the solar system that will grab our attention is the alpha Centauri star system and its earthlike planet, Proxima Centauri b.
“This is the closest exoplanet to us. The star is small and cold, the planet revolves next to it. It is interesting for us whether there is life there, because, as calculations show, there are conditions for liquid water on the surface,”the astronomer clarifies.
In flight, we examine the nearest nebulae and star clusters - Lagoon, Eagle, Omega, Triple. We meet black holes (if, of course, we can recognize them), neutron stars, planetary systems, clouds of molecular gas - especially dense and cold objects in comparison with the interstellar medium. Mostly they consist of hydrogen molecules, but rather complex organic matter is not excluded. In theory, you can figure out how to replenish water or alcohol in them.
In fact, according to the scientist, molecular clouds are an important source of knowledge about the chemical evolution of the universe. Where, for example, does water come from on Earth? Previously, it was thought that comets carried it, but the analysis of samples from the Churyumov-Gerasimenko comet refutes this version.
The Milky Way, where the Earth and solar system are located, contains about 400 billion stars.
On the approaches to the galactic core
Then we cross the arms of Sagittarius, Shield, Centauri and come to the border of the Milky Way core, the so-called bulge - a bubble with many stars. Figuratively speaking, if the galactic disk is a protein, then the bulge is the yolk.
“The sky is so star-studded that no lighting is needed. The density of the “population” here is twenty thousand times higher than in our part of the Galaxy,”continues Evgeny Semenko.
The stars are more massive here, so their life cycle is faster. In the interstellar medium there are more heavy elements left over from supernova explosions. Studying how the chemical composition of stars changes, they reconstruct the evolution of the Galaxy. No wonder this popular area of modern astrophysics is called galactic archeology.
Directly in the center of the Milky Way is the strongest source of radio waves in the Galaxy - Sagittarius A *. Stars revolve around it at breakneck speeds - about a thousand kilometers per second. Scientists have been following them for several years and, based on the change in trajectories, estimated the mass of the object - four million suns. It is believed to be a supermassive black hole. Such an object creates a monstrous force of attraction. We will have to fly around it.
Accretion disk of a black hole, which arises from the fall of matter towards the black hole. This is how it will look to an outside observer.
Tatiana Pichugina