Proxima Centauri is the star closest to Earth. It got its name from the Latin word proxima, which means "nearest". The distance from it to the Sun is 4.22 light years. However, despite the fact that the star is closer to us than the Sun, it can only be seen through a telescope. It is so small that nothing was known of its existence until 1915. The discoverer of the star was Robert Innes, an astronomer from Scotland.

Alpha Centauri

Proxima is part of the system In addition to it, it also includes two more stars: Alpha Centauri A and Alpha Centauri B. They are much brighter and more noticeable than Proxima. So, star A, the brightest in this constellation, is located at a distance of 4.33 light years from the Sun. It is called the Rigel Centauri, which translates as "The Leg of the Centaur." This star is somewhat reminiscent of our Sun. Probably because of its brightness. Unlike Proxima Centauri, it has been known since ancient times, as it is very visible in the night sky.

Alpha Centauri B is also not inferior to its "sister" in brightness. Together they form a tight binary system. Proxima Centauri is far enough away from them. Between the stars - a distance of thirteen thousand astronomical units (this is farther than from the Sun to the planet Neptune as much as four hundred times!).

All stars in the Centauri system orbit around their common center of mass. Only Proxima moves very slowly: the period of its revolution takes millions of years. Therefore, this star will remain the closest to Earth for a very long time.

Quite small

The star Proxima Centauri is not only the closest star from the constellation to us, but it is also the smallest. Its mass is so tiny that it is barely enough to support the processes of formation of helium from hydrogen, which are necessary for existence. The star is very dim. Proxima is much lighter than the Sun, about seven times. And the temperature on its surface is much lower: "only" three thousand degrees. In terms of brightness, Proxima is one hundred and fifty times inferior to the Sun.

red dwarfs

The small star Proxima belongs to the spectral type M with a very low luminosity. Another name for celestial bodies of this class is widely known - red dwarfs. Stars with such a small mass are the most interesting objects. Their internal structure is somewhat similar to the structure of giant planets such as Jupiter. The matter of red dwarfs is in an exotic state. In addition, there are suggestions that planets that are located near such stars may be habitable.

Red dwarfs live very long lives, much longer than any other stars. They evolve very slowly. Any nuclear reactions inside them begin to occur only a few billion years after their birth. The lifetime of a red dwarf is longer than the lifetime of the entire universe! So, in the far, far future, when more than one star like the Sun goes out, the red dwarf Proxima Centauri will still shine dimly in the darkness of space.

In general, red dwarfs are the most frequent stars in our galaxy. They make up over 80% of all stellar bodies. And here is the paradox: they are completely invisible! You won't see any of them with the naked eye.

Measurement

Until now, the ability to accurately measure the size of such small stars as red dwarfs was simply not possible due to their weak luminosity. But today this problem has been solved with the help of a special VLT interferometer (VLT is an abbreviation for the English Very Large Telescope). This is an apparatus based on two large 8.2-meter VLT telescopes located at the Paranal Astronomical Observatory (ESO). These two huge telescopes, separated by 102.4 meters from each other, make it possible to measure with an accuracy that is simply not possible with other devices. So the astronomers of the Geneva Observatory for the first time received the exact dimensions of such a small star.

Changeable Centauri

In terms of size, Proxima Centauri borders between a real star, a planet, and yet it is a star. Its mass and diameter are one-seventh of the mass, as well as, respectively. The star is one hundred and fifty times more massive than the planet Jupiter, but weighs one and a half times less. If Proxima Centauri weighed even less, then it would simply not be able to become a star: there would not be enough hydrogen in its depths to emit light. In this case, it would be an ordinary brown dwarf (i.e., dead), and not a real star.

Proxima itself is very dim heavenly body. In the normal state, its luminosity reaches no more than 11m. It looks bright only in pictures taken by huge telescopes, such as, for example, Hubble. However, sometimes the brightness of a star is sharply and significantly enhanced. Scientists explain this fact by the fact that Proxima Centauri belongs to the class of so-called changeable, or flaring, stars. This is caused by strong flashes on its surface, which are the results of violent convection processes. They are somewhat similar to those that occur on the surface of the Sun, only much stronger, which even leads to a change in the brightness of the star.

Still just a child

These violent processes and outbreaks indicate that the nuclear reactions taking place in the depths of Proxima Centauri have not yet stabilized. The conclusions of scientists: this is still a very young star by the standards of space. Although its age is quite comparable with the age of our Sun. But Proxima is a red dwarf, so they can't even be compared. Indeed, like other "red brothers", it will burn its nuclear fuel very slowly and economically, and therefore shine for a very, very long time - approximately three hundred times longer than our entire Universe! What is there to say about the Sun ...

Many science fiction writers believe that Proxima Centauri is the most suitable star for space exploration and adventure. Some believe that her universe hides planets where other civilizations can be found. Maybe it is, but that's just the distance from the Earth to Proxima Centauri - more than four light years. So, although it is the closest, it is still far away.

What is the distance from Earth to the nearest star, Proxima Centauri?

1. Consider - 3.87 light years * for 365 days * 86400 (number of seconds in a day) * 300,000 (speed of light km / s) \u003d (approximately) like Vladimir Ustinov, and our Sun is only 150 million km
2. Perhaps there are stars closer (the sun does not count), only they are very small (a white dwarf for example), but they have not yet been discovered. 4 light years is still very far
3. The nearest star from the Sun is Proxima Centauri. Its diameter is seven times smaller than the sun, the same applies to its mass. Its luminosity is 0.17% of the luminosity of the Sun, or only 0.0056% in the spectrum visible to the human eye. This explains the fact that it is impossible to see it with the naked eye, and that it was discovered only in the 20th century. The distance from the Sun to this star is 4.22 light years. Which by space standards is almost close. After all, even the gravity of our Sun extends to about half this distance! However, for humanity, this distance is truly enormous. Planetary distances are measured in light years. How long does light travel in a vacuum in 365 days? This value is 9,640 billion kilometers. Let's take a few examples to understand distances. The distance from the Earth to the Moon is 1.28 light seconds, and with current technology, the journey takes 3 days. Distances between planets in our solar system range from 2.3 light minutes to 5.3 light hours. In other words, the longest journey will take just over 10 years on an unmanned spacecraft. Now consider how much time we need to fly to Proxima Centauri. Currently the speed champion is the unmanned spaceship Helios 2. Its speed is 253,000 km/h or 0.02334% of the speed of light. Having calculated, we find out that it will take us 18,000 years to get to the nearest star. With the current level of technology development, we can only ensure the operation of a spacecraft for 50 years.
4. It's hard to imagine distances in numbers. If our sun is reduced to the size of a match head, then the distance to the nearest star will be approximately equal to 1 kilometer.
5. To Proxima Centauri about 40,000,000,000,000 km ... 4.22 light years .. To Alpha Centauri 4.37 light. of the year…
6. 4 light years (approximately 37,843,200,000,000 km)
7. You are confusing something, dear colleague. The nearest star is the Sun. 8 minutes with a little from no light goes 🙂
8. Before Proxima: 4.22 (+- 0.01) St. years. Or 1.295 (+-0.004) parsec. Taken from here.
9. to Proxima Centauri 4.2 light years is 41,734,219,479,449.6 km, if 1 light year is 9,460,528,447,488 km
10. 4.5 light years (1 parsec?)
11. There are stars in the universe that are so far away from us that we don't even have the ability to know their distance or set their number. But how far is the nearest star from Earth?

    The distance from the Earth to the Sun is 150,000,000 kilometers. Since light travels at 300,000 km/sec, it takes 8 minutes for it to travel from the Sun to the Earth.

    The closest stars to us are Proxima Centauri and Alpha Centauri. The distance from them to the Earth is 270,000 times greater than the distance from the Sun to the Earth. That is, the distance from us to these stars is 270,000 times more than 150,000,000 kilometers! Their light takes 4.5 years to reach Earth.

    The distance to the stars is so great that it was necessary to develop a unit for measuring this distance. It's called a light year. This is the distance light travels in one year. This is approximately 10 trillion kilometers (10,000,000,000,000 km). The distance to the nearest star exceeds this distance by 4.5 times.

    Of all the stars in the sky, only 6,000 can be seen without a telescope, with the naked eye. Not all of these stars are visible from the UK.

    In fact, looking at the sky and watching the stars, they can be counted a little over a thousand. A powerful telescope can detect many, many times more.

> Proxima Centauri

- a red dwarf of the constellation Centaurus and the star closest to Earth: description and characteristics with a photo, how to find it in the sky, distance, facts.

(Alpha Centauri C) is the closest single alien star to Earth. It is located in the constellation Centaurus. Distance from solar system to Proxima Centauri is 4.243 light years. From Latin, "proxima" is translated as "near / closer to." The distance from the stellar object C to the Alpha Centauri AB system is 0.237 light years.

Proxima Centauri is believed to be the third member of the Alpha Centauri AB system, but its orbital period is as long as 500,000 years. Before us is a red dwarf, which is too weak in terms of luminosity to find it without using a telescope. The magnitude of the star reaches 11.05. Robert Innes found her in 1915.

Proxima Centauri belongs to the class of flare stars - variables that randomly increase in brightness due to magnetic activity. This leads to the creation x-rays. By mass, the star reaches 1/8 of the sun, and by diameter - 1/7 of the sun.

Proxima Centauri is slowly ejecting energy, so it will remain in the main sequence for the next 4 trillion years, which is 300 times the current age of the universe. You can admire photos of the star from the Hubble Space Telescope or use our star map to find Proxima Centauri in the sky yourself.

The Hubble telescope was able to capture the bright radiance of the nearest star - Proxima Centauri. It is located in the constellation Centaurus at a distance of 4 light years. It seems bright here, but it cannot be found with the naked eye. The average visibility is extremely low, and in terms of massiveness it reaches only the 8th part of the sun. But periodically the brightness of the star increases. Proxima Centauri belongs to the category of flare stars. That is, the processes of convection inside it lead to random changes in luminosity. It also hints at the long existence of the star. Scientists believe that it will remain in the main sequence stage for another 4 trillion years, which is 300 times the current universal age. The observations were made by Planetary Camera 2 of the Hubble Space Telescope. Proxima Centauri enters the system with two members, A and B, out of frame.

It is believed that as a result, Proxima Centauri will begin to cool and decrease in size, changing from red to blue. At this point, the brightness will increase to 2.5% solar. When the hydrogen fuel in the stellar core runs out, Proxima Centauri will transform into a white dwarf.

The star can be observed by those who live south of 27 ° N. sh. The view requires a minimum of a 3.1-inch telescope and ideal viewing conditions.

For 32,000 years, Proxima Centauri was considered the closest star to the Sun and will remain in this position for another 33,000 years. Then the star Ross 248, a red dwarf located in the constellation Andromeda, will take its place.

For residents of the northern latitudes, Barnard seems to be the closest star to Earth - this is a red dwarf in the constellation Ophiuchus. If we are looking for the nearest star visible to the naked eye, then this is Sirius, 8.6 light years away from us.

Proxima Centauri is the closest star to Earth

Proxima Centauri is 271,000 AU distant from us. (4.22 light years). It is closer to the Alpha Centauri AB system, which is 4.35 light years away from the solar system.

We are talking about huge distances. The Voyager 1 spacecraft is moving at a speed of 17.3 km/s (faster than a bullet). If he went to the star Proxima Centauri, he would have spent 73,000 years on the trip. If he could accelerate to the speed of light, it would take 4.22 years.

The distance from the solar system to the star Proxima Centauri was calculated using the parallax method. Scientists measured the position of the star in relation to other stars in the sky, and then re-measured after 6 months, when the Earth was on the other side of the orbit. Although Proxima Centauri is the closest, it is believed that between us and the star there may still be unnoticed brown dwarfs.

A detailed survey of the system struck superterrestrial planets and brown dwarfs out of the habitable zone. Proxima Centauri is a bursting stellar type, so it may not support life on potential planets at all. Any worlds in orbit around the star can be found with the help of the James Webb telescope, which is scheduled to launch in 2021.

Facts about the star Proxima Centauri

In 1915, the star Proxima Centauri was discovered by Robert Innes. He noticed that it shares a common correct motion with the star Alpha Centauri.

In 1917 John Voyet used trigonometric measurement parallax and found that the star is at about the same distance from us as the binary system Alpha Centauri. In 1928, Harold Alden used the same method and realized that Proxima Centauri was closer to us at a parallax of 0.783″.

The flaring nature of the star was noted by Harlow Shapley in 1951. If compared with archival images, it can be seen that its value has increased by 8%. This helped Proxima Centauri become the most active flare star.

Proxima Centauri belongs to the class M5.5 - it is a red dwarf with an extremely low mass. Because of this, its interior is convective, where helium circulates throughout the star rather than pooling in the core.

Stellar flares can be as large as the star itself, and the temperature rises to 27 million K. This is enough to create X-rays. In terms of luminosity, Proxima Centauri reaches only 0.17% of the solar, in diameter - 1/7 of the solar and about 1.5 times larger than Jupiter.

The massiveness of Proxima Centauri is 12.3% solar, and the surface temperature rises to 3500 K. The star will make its closest approach to the Sun in 26700 years, reducing the distance to 3.11 light years. If we looked at the Sun from the position of Proxima Centauri, we would see a bright star in the territory of the constellation Cassiopeia. The observed magnitude of the star is 0.4.

Alpha Centauri C

Proxima Centauri is part of the Alpha Centauri AB system and is 0.21 light-years away from the stars. At the same time, the star spends 500,000 years to rotate in orbit. Most likely, there is a gravitational connection between them.

A three-component system in the constellation Centaurus is formed when a low-mass star is attracted by a more massive binary system within a star cluster until it dissipates. Alpha Centauri and Proxima Centauri share a common regular motion with a triple, two doubles, and six single stars. This suggests that all these stars are capable of forming a moving stellar group.

The star Alpha Centauri is easy to find from southern latitudes, as it is brighter than the stars that indicate the Southern Cross asterism. A binary star system can be resolved with a small telescope. But Proxima Centauri is 2 degrees south and you will need at least a large amateur telescope to observe.

Physical characteristics and orbit of the star Proxima Centauri

• Constellation: Centaurus.
• Spectral class M5.5 Ve.
• Coordinates: 14h 29m 42.9487s (right ascension), -62° 40" 46.141" (declination).
• Distance: 4.243 light years.
• Apparent magnitude (V): 11.05.
• Apparent magnitude (J): 5.35.
• Absolute value: 15.49.
• Luminosity: 0.0017 solar.
• Massiveness: 0.123 solar.
• Radius: 0.141 solar.
• Temperature mark: 3042 K.
• Surface density: 5.20.
• Rotation: 83.5 days.
• Rotation speed: 2.7 km/s.
• Names: Proxima Centauri, Alpha Centauri C, CCDM J14396-6050C, GCTP 3278.00, GJ 551, HIP 70890, LFT 1110, LHS 49, LPM 526, LTT 5721, NLTT 37460, V645 Centauri.

Alpha Centauri is the target of spacecraft flights in many works belonging to the science fiction genre. This star closest to us refers to the celestial drawing, embodying the legendary centaur Chiron, according to Greek mythology, former teacher Hercules and Achilles.

Modern researchers, like writers, tirelessly return to this star system in their thoughts, since it is not only the first candidate for a long-term space expedition, but also the possible owner of a populated planet.

Structure

The Alpha Centauri star system includes three space objects: two stars with the same name and designations A and B, as well as similar stars are characterized by the proximity of two components and the remote one - the third. Proxima is just the last one. The distance to Alpha Centauri with all its elements is approximately 4.3 There are currently no stars located closer to the Earth. At the same time, the fastest way to fly to Proxima: we are separated by only 4.22 light years.

solar relatives

Alpha Centauri A and B differ from their companion not only in their distance from the Earth. They, unlike Proxima, are in many ways similar to the Sun. Alpha Centauri A or Rigel Centaurus (translated as "Centaur's foot") is the brighter component of the pair. Toliman A, as this star is also called, is a yellow dwarf. From the Earth, it is perfectly visible, since it has a zero magnitude. This parameter makes it the fourth brightest spot in the night sky. The size of the object almost also coincides with the solar one.

The star Alpha Centauri B is inferior to our luminary in mass (about 0.9 of the values ​​of the corresponding parameter of the Sun). It belongs to the objects of the first magnitude, and its luminosity level is approximately two times less than that of the main star of our piece of the Galaxy. The distance between two neighboring companions is 23 astronomical units, that is, they are located 23 times farther apart than the Earth is from the Sun. Toliman A and Toliman B together revolve around the same center of mass with a period of 80 years.

recent discovery

Scientists, as already mentioned, have high hopes for the discovery of life in the vicinity of the star Alpha Centauri. The planets supposed to exist here may resemble the Earth in the same way that the components of the system themselves resemble our star. Until recently, however, no such cosmic bodies were found near a star. The distance does not allow direct observation of the planets. Obtaining evidence of the existence of an earth-like object became possible only with the improvement of technology.

Using the method of radial velocities, scientists were able to detect very small fluctuations of Toliman B, which occur under the influence of gravitational forces planets revolving around it. Thus, evidence was obtained for the existence of at least one such object in the system. The wobbles caused by the planet appear as its displacement of 51 cm per second forward and then back. Under the conditions of the Earth, such a movement, even of the largest body, would be very noticeable. However, at a distance of 4.3 light years, detection of such a wobble seems impossible. However, it was registered.

Sister of the Earth

The found planet revolves around Alpha Centauri B in 3.2 days. It is located very close to the star: the radius of the orbit is ten times smaller than the corresponding parameter characteristic of Mercury. The mass of this space object is close to that of the earth and is approximately 1.1 of the mass of the Blue Planet. This is where the similarity ends: the proximity, according to scientists, suggests that the emergence of life on the planet is impossible. The energy of the luminary, reaching its surface, heats it too much.

nearest

The third component that makes the entire constellation famous is Alpha Centauri C or Proxima Centauri. The name of the cosmic body in translation means "nearest". Proxima stands at a distance of 13,000 light years from its companions. This object is the eleventh red dwarf, small (about 7 times smaller than the Sun) and very dim. It is impossible to see it with the naked eye. Proxima is characterized by a “restless” state: a star is capable of changing its brightness twice in a few minutes. The reason for this "behavior" in the internal processes occurring in the depths of the dwarf.

dual position

Proxima has long been considered the third element of the Alpha Centauri system, orbiting the pair A and B in about 500 years. However, in Lately the opinion is gaining strength that the red dwarf has nothing to do with them, and the interaction of three cosmic bodies is a temporary phenomenon.

The reason for doubt was the data that said that a close-knit pair of stars does not have enough attraction to hold Proxima as well. The information received in the early 90s of the last century needed additional confirmation for a long time. Recent observations and calculations of scientists did not give a definite answer. According to assumptions, Proxima can still be part of a triple system and move around a common gravitational center. At the same time, its orbit should look like an elongated oval, and the most distant point from the center is the one in which the star is observed now.

Projects

Be that as it may, it is planned to fly to Proxima in the first place, when it becomes possible. The journey to Alpha Centauri, with the current level of development of space technology, can last more than 1000 years. Such a time period is simply unthinkable, so scientists are actively looking for ways to reduce it.

A team of NASA researchers led by Harold White is developing Project Speed, which should result in a new engine. Its feature will be the ability to overcome the speed of light, so that the flight from the Earth to the nearest star will be only two weeks. Such a miracle of technology will become a real masterpiece of the close-knit work of theoretical physicists and experimenters. So far, however, a ship that overcomes the speed of light is a matter of the future. According to Mark Millis, who once worked at NASA, such technologies, given the current speed of progress, will not become a reality until two hundred years later. Reducing the period is possible only if a discovery is made that can radically change the existing ideas about space flights.

For now, Proxima Centauri and its companions remain an ambitious goal, unattainable in the near future. Technique, however, is constantly being improved, and new information about the characteristics of the star system is clear evidence of this. Even today, scientists can do a lot of things that 40-50 years ago they could not even dream of.

At some point in our lives, each of us has asked this question: how long does it take to fly to the stars? Is it possible to make such a flight in one human life, can such flights become the norm of everyday life? There are many answers to this complex question, depending on who asks. Some are simple, others are more difficult. To find a comprehensive answer, there are too many things to consider.

The answer to this question is not so simple.

Unfortunately, no real estimates exist to help find such an answer, and this is frustrating for futurologists and interstellar travel enthusiasts. Like it or not, space is very big (and complex) and our technology is still limited. But if we ever decide to leave the "native nest", we will have several ways to get to the nearest star system in our galaxy.

The closest star to our Earth is quite an “average” star according to the Hertzsprung-Russell “main sequence” scheme. This means that the star is very stable and provides enough sunlight for life to develop on our planet. We know that there are other planets orbiting stars near our solar system, and many of these stars are similar to our own.

Possible habitable worlds in the universe

In the future, if humanity wishes to leave the solar system, we will have a huge selection of stars to which we could go, and many of them may well have favorable conditions for life. But where are we going and how long will it take us to get there? Don't forget that this is all just speculation and there are no guidelines for interstellar travel at this time. Well, as Gagarin said, let's go!

As already noted, the closest star to our solar system is Proxima Centauri, and therefore it makes a lot of sense to start planning an interstellar mission from it. As part of the Alpha Centauri triple star system, Proxima lies 4.24 light years (1.3 parsecs) from Earth. Alpha Centauri is, in fact, the most bright Star of the three in the system, part of a close binary 4.37 light-years from Earth - while Proxima Centauri (the dimmest of the three) is an isolated red dwarf 0.13 light-years from the binary.

And although conversations about interstellar travel evoke thoughts of all kinds of travel " faster speed from warp speeds and wormholes to subspace drives, such theories are either highly fictional (sort of) or only exist in science fiction. Any mission in deep space spread over generations of people.

So, starting with one of the slowest forms of space travel, how long does it take to get to Proxima Centauri?

Modern methods

The question of estimating the duration of travel in space is much simpler if existing technologies and bodies in our solar system are involved in it. For example, using the technology used by 16 hydrazine monopropellant engines, you can reach the moon in just 8 hours and 35 minutes.

There is also the SMART-1 mission of the European Space Agency, which moved to the Moon using ion propulsion. With this revolutionary technology, a variant of which was also used by the Dawn space probe to reach Vesta, it took the SMART-1 mission a year, a month and two weeks to get to the moon.

Ion thruster

From fast rocket spacecraft to economical ion propulsion, we have a couple of options for getting around local space - plus you can use Jupiter or Saturn as a huge gravitational slingshot. However, if we plan to go a little further, we will have to increase the power of technology and explore new opportunities.

When we talk about possible methods, we are talking about those that involve existing technologies, or those that do not yet exist but are technically feasible. Some of them, as you will see, are time-tested and confirmed, while others remain in question. In short, they represent a possible, but very time-consuming and financially expensive scenario for traveling even to the nearest star.

Ionic movement

Now the slowest and most economical form of propulsion is the ion propulsion. A few decades ago, ionic motion was considered the subject of science fiction. But in recent years ion thruster support technologies have moved from theory to practice, and with great success. The SMART-1 mission of the European Space Agency is an example of a successful mission to the Moon in 13 months of spiral motion from the Earth.

SMART-1 used solar-powered ion thrusters, in which electrical energy was collected by solar panels and used to power the Hall effect motors. It took only 82 kilograms of xenon fuel to get SMART-1 to the Moon. 1 kilogram of xenon fuel provides a delta-V of 45 m/s. This is an extremely efficient form of movement, but far from the fastest.

One of the first missions to use ion thruster technology was the Deep Space 1 mission to Comet Borrelli in 1998. The DS1 also used a xenon ion engine and used 81.5 kg of fuel. In 20 months of thrust, the DS1 reached speeds of 56,000 km/h at the time of the comet's flyby.

Ion thrusters are more economical than rocket technologies because their thrust per unit mass of propellant (specific impulse) is much higher. But ion engines take a long time to get up to speed. spacecraft to significant speeds, and the maximum speed depends on fuel support and power generation volumes.

Therefore, if ion propulsion is used in a mission to Proxima Centauri, the engines must have a powerful source of energy (nuclear energy) and large fuel reserves (albeit less than conventional rockets). But if you start from the assumption that 81.5 kg of xenon fuel translates into 56,000 km / h (and there will be no other forms of movement), you can make calculations.

At a maximum speed of 56,000 km/h, Deep Space 1 would take 81,000 years to cover the 4.24 light-years between Earth and Proxima Centauri. In time, this is about 2700 generations of people. It's safe to say that an interplanetary ion drive would be too slow for a manned interstellar mission.

But if the ion thrusters are larger and more powerful (i.e., the ion outflow rate is much faster), if there is enough propellant to last the full 4.24 light years, the travel time will be greatly reduced. But there will still be much more than a human lifespan.

Gravity maneuver

Most fast way space travel is the use of gravity assist. This method involves the spacecraft using the relative motion (i.e. orbit) and gravity of the planet to change path and speed. Gravity maneuvers are an extremely useful spaceflight technique, especially when using the Earth or another massive planet (like a gas giant) for acceleration.

The Mariner 10 spacecraft was the first to use this method, using the gravitational pull of Venus to accelerate towards Mercury in February 1974. In the 1980s, the Voyager 1 probe used Saturn and Jupiter for gravitational maneuvers and acceleration to 60,000 km / h, followed by an exit into interstellar space.

The Helios 2 mission, which began in 1976 and was supposed to explore the interplanetary medium between 0.3 AU. e. and 1 a. e. from the Sun, holds the record for the highest speed developed with the help of a gravitational maneuver. At that time, Helios 1 (launched in 1974) and Helios 2 held the record for the closest approach to the Sun. Helios 2 was launched by a conventional rocket and put into a highly elongated orbit.

Mission Helios

Due to the large eccentricity (0.54) of the 190-day solar orbit, Helios 2 managed to achieve a maximum speed of over 240,000 km/h at perihelion. This orbital speed was developed due to only the gravitational attraction of the Sun. Technically, Helios 2's perihelion speed was not the result of a gravitational maneuver, but a maximum orbital speed, but the craft still holds the record for the fastest man-made object.

If Voyager 1 were moving towards the red dwarf Proxima Centauri at a constant speed of 60,000 km/h, it would take 76,000 years (or more than 2,500 generations) to cover this distance. But if the probe were to reach the record speed of Helios 2 - a constant speed of 240,000 km / h - it would take 19,000 years (or more than 600 generations) to travel 4.243 light years. Substantially better, though not close to practical.

EM Drive Electromagnetic Motor

Another proposed method of interstellar travel is the EM Drive. Proposed back in 2001 by Roger Scheuer, the British scientist who created Satellite Propulsion Research Ltd (SPR) to carry out the project, the engine is based on the idea that electromagnetic microwave cavities can directly convert electrical energy into thrust.

EM Drive - resonant cavity motor

While traditional electromagnetic thrusters are designed to propel a certain mass (like ionized particles), this particular propulsion system is independent of mass response and does not emit directional radiation. In general, this engine was met with a fair amount of skepticism, largely because it violates the law of conservation of momentum, according to which the momentum of the system remains constant and cannot be created or destroyed, but only changed by force.

However, recent experiments with this technology have obviously led to positive results. In July 2014, at the 50th AIAA/ASME/SAE/ASEE Joint Propulsion Conference in Cleveland, Ohio, NASA advanced jet scientists announced they had successfully tested a new electromagnetic propulsion design.

In April 2015, scientists from NASA Eagleworks (part of the Johnson Space Center) said they had successfully tested this engine in a vacuum, which could indicate a possible application in space. In July of the same year, a group of scientists from the Space Systems Department of Dresden technological university developed her own version of the engine and observed tangible thrust.

In 2010, Professor Zhuang Yang from the Northwestern polytechnic university in Xi'an, China, has begun publishing a series of articles on its research into EM Drive technology. In 2012, she reported a high power input (2.5 kW) and a recorded thrust of 720 mn. It also conducted extensive testing in 2014, including internal temperature measurements with built-in thermocouples, which showed that the system worked.

NASA's prototype (which was given a power estimate of 0.4 N/kilowatt) calculated that an electromagnetically propelled spacecraft could make a trip to Pluto in less than 18 months. This is six times less than the New Horizons probe, which was moving at a speed of 58,000 km / h, required.

Sounds impressive. But even in this case, the ship on electromagnetic engines will fly to Proxima Centauri for 13,000 years. Close, but still not enough. In addition, until all the e is dotted in this technology, it is too early to talk about its use.

Nuclear thermal and nuclear electrical propulsion

Another possibility to carry out interstellar flight is to use a spacecraft equipped with nuclear engines. NASA has been exploring such options for decades. A nuclear thermal propulsion rocket could use uranium or deuterium reactors to heat the hydrogen in the reactor, turning it into ionized gas (hydrogen plasma), which would then be directed into the rocket nozzle, generating thrust.

Rockets I'm nuclear powered

A nuclear electric-powered missile includes the same reactor, which converts heat and energy into electricity, which then powers an electric motor. In both cases, the rocket will rely on nuclear fusion or fission for thrust, rather than the chemical propellants that all modern space agencies run on.

Compared to chemical engines, nuclear engines have undeniable advantages. First, it has a virtually unlimited energy density compared to propellant. In addition, a nuclear engine will also produce powerful thrust compared to the amount of fuel used. This will reduce the amount of fuel required, and at the same time the weight and cost of a particular device.

Although thermal nuclear engines have not yet gone into space, their prototypes have been created and tested, and even more have been proposed.

And yet, despite the advantages in fuel economy and specific impulse, the best proposed nuclear thermal engine concept has a maximum specific impulse of 5000 seconds (50 kN s/kg). Using nuclear engines powered by nuclear fission or fusion, NASA scientists could get a spacecraft to Mars in just 90 days if the Red Planet were 55,000,000 kilometers from Earth.

But if we're talking about the journey to Proxima Centauri, it would take centuries for a nuclear rocket to accelerate to a substantial fraction of the speed of light. Then it will take several decades of travel, and after them many more centuries of deceleration on the way to the goal. We are still 1000 years away from our destination. What is good for interplanetary missions is not so good for interstellar missions.

nuclear power plant

Nuclear propulsion is a theoretically possible "engine" for fast space travel. The concept was originally proposed by Stanislaw Ulam in 1946, a Polish-American mathematician who took part, and preliminary calculations were made by F. Reines and Ulam in 1947. The Orion project was launched in 1958 and lasted until 1963.

Led by Ted Taylor of General Atomics and physicist Freeman Dyson of the Institute for Advanced Study at Princeton, Orion would use the power of impulse nuclear explosions to provide tremendous thrust with very high specific impulse.

Orion was supposed to use the power of pulsed nuclear explosions

In a nutshell, the Orion project involves a large spacecraft that gains speed by supporting thermonuclear warheads, ejecting bombs from behind and accelerating on the blast wave that goes into the rear "pusher", the push panel. After each push, the force of the explosion is absorbed by this panel and converted into forward motion.

Although according to modern standards this design can hardly be called elegant, the advantage of the concept is that it provides high specific thrust - that is, it extracts maximum amount energy from a source of fuel (in this case, nuclear bombs) at minimal cost. In addition, this concept can theoretically accelerate very high speeds, up to 5% of the speed of light (5.4 x 107 km/h) according to some estimates.

Of course, this project has inevitable disadvantages. On the one hand, a ship of this size would be extremely expensive to build. Dyson estimated in 1968 that the Orion spacecraft hydrogen bombs would have weighed between 400,000 and 4,000,000 metric tons. And at least three-quarters of that weight will come from nuclear bombs, each of which weighs about one ton.

Dyson's conservative calculations showed that the total cost of building the Orion would have been $367 billion. Adjusted for inflation, that comes out to $2.5 trillion, which is quite a lot. Even with the most modest estimates, the device will be extremely expensive to manufacture.

There is also the small issue of the radiation it will emit, not to mention the nuclear waste. It is believed that this is the reason why the project was canceled under the partial test ban treaty of 1963, when world governments sought to limit nuclear testing and stop the excessive release of radioactive fallout into the planet's atmosphere.

Nuclear fusion rockets

Another possibility of using nuclear energy is in thermonuclear reactions to produce thrust. Under this concept, energy must be created during the ignition of the pellets of a mixture of deuterium and helium-3 in the reaction chamber by inertial confinement using electron beams (similar to what is done at the National Ignition Facility in California). Such a fusion reactor would explode 250 pellets per second, creating a high-energy plasma that would then be redirected into a nozzle, creating thrust.

Project Daedalus never saw the light of day

Like a rocket that relies on a nuclear reactor, this concept has advantages in terms of fuel efficiency and specific impulse. It is estimated that the speed should reach 10,600 km / h, which is much higher than the speed limits of conventional missiles. Moreover, this technology has been actively studied over the past few decades, and many proposals have been made.

For example, between 1973 and 1978, the British Interplanetary Society conducted a study on the possibility of Project Daedalus. Drawing on current knowledge and fusion technology, scientists have called for the construction of a two-stage unmanned science probe that could reach Barnard's Star (5.9 light years from Earth) in a human lifetime.

The first stage, the largest of the two, would last for 2.05 years and accelerate the craft to 7.1% of the speed of light. Then this stage is discarded, the second one is ignited, and the device accelerates to 12% of the speed of light in 1.8 years. Then the engine of the second stage is turned off, and the ship flies for 46 years.

Agree, it looks very nice!

Project Daedalus estimated that the mission would have taken 50 years to reach Barnard's Star. If to Proxima Centauri, the same ship will get there in 36 years. But, of course, the project includes a lot of unresolved issues, in particular, unsolvable using modern technologies- and most of them are still unresolved.

For example, there is practically no helium-3 on Earth, which means that it will have to be mined elsewhere (most likely on the Moon). Second, the reaction that drives the apparatus requires the energy emitted to be much greater than the energy expended to start the reaction. And although experiments on Earth have already surpassed the break-even point, we are still far from the amount of energy that can power an interstellar vehicle.

Thirdly, the question of the cost of such a vessel remains. Even by the modest standards of Project Daedalus drone, a fully equipped vehicle would weigh 60,000 tons. To give you an idea, the gross weight of the NASA SLS is just over 30 metric tons, and the launch alone will cost $5 billion (2013 estimate).

In short, a fusion rocket would not only be too expensive to build, but would require a level of fusion reactor far beyond our capabilities. Icarus Interstellar, international organization citizen scientists (some of whom worked for NASA or ESA) are trying to revive the concept with Project Icarus. Formed in 2009, the group hopes to make the synthesis movement (and others) possible in the foreseeable future.

Thermonuclear ramjet

Also known as the Bussard ramjet engine, the engine was first proposed by physicist Robert Bussard in 1960. At its core, this is an improvement on the standard fusion missile, which uses magnetic fields to compress hydrogen fuel to the fusion start point. But in the case of a ramjet, a huge electromagnetic funnel sucks in hydrogen from the interstellar medium and pours it into the reactor as fuel.

As the craft picks up speed, the reaction mass enters a confining magnetic field that compresses it until fusion begins. The magnetic field then directs the energy into the rocket's nozzle, accelerating the ship. Since no amount of fuel tanks will slow it down, a fusion ramjet can reach speeds of the order of 4% of light speed and go anywhere in the galaxy.

However, this mission has a lot of potential drawbacks. For example, the problem of friction. The spacecraft relies on a high fuel collection rate, but will also encounter a lot of interstellar hydrogen and lose speed - especially in dense regions of the galaxy. Secondly, there is not much deuterium and tritium (which are used in reactors on Earth) in space, and the synthesis of ordinary hydrogen, which is abundant in space, is still beyond our control.

However, science fiction loved this concept. The most famous example is perhaps the franchise " Star Trek", where "Bussard collectors" are used. In reality, our understanding of fusion reactors is far from being as perfect as we would like.

laser sail

Solar sails have long been considered effective way conquest of the solar system. In addition to being relatively simple and cheap to make, they have a big plus: they don't need fuel. Instead of using fuel-hungry rockets, the sail uses the radiation pressure from the stars to propel ultra-thin mirrors to high speeds.

However, in the case of an interstellar flight, such a sail would have to be pushed by focused beams of energy (laser or microwaves) in order to accelerate to a speed close to the speed of light. The concept was first proposed by Robert Forward in 1984, a physicist at the Hughes Aircraft Laboratory.

What is there in space a lot? That's right - sunshine.

His idea retains the advantages of a solar sail in that it does not require fuel on board, and also in that laser energy does not dissipate over distance in the same way as solar radiation. Thus, although it will take some time for the laser sail to accelerate to near-light speed, it will subsequently be limited only by the speed of light itself.

According to a study by Robert Frisby in 2000, director of advanced movement concepts research at the Laboratory jet propulsion NASA, a laser sail will accelerate to half the speed of light in less than ten years. He also calculated that a sail with a diameter of 320 kilometers could reach Proxima Centauri in 12 years. Meanwhile, the sail, 965 kilometers in diameter, will arrive in place in just 9 years.

However, such a sail will have to be built from advanced composite materials to avoid melting. Which will be especially difficult given the size of the sail. The cost is even worse. According to Frisbee, the lasers would need a steady stream of 17,000 terawatts of power, about the amount the entire world consumes in a single day.

Antimatter Engine

Fans of science fiction are well aware of what antimatter is. But in case you forgot, antimatter is matter made up of particles that have the same mass as normal particles but opposite charge. An antimatter drive is a hypothetical drive based on interactions between matter and antimatter to generate energy, or create thrust.

Hypothetical antimatter engine

In short, the antimatter engine uses colliding particles of hydrogen and antihydrogen. The energy emitted during the annihilation process is comparable in volume to the energy of a thermonuclear bomb explosion accompanied by a stream of subatomic particles - pions and muons. These particles, which travel at one-third the speed of light, are redirected into a magnetic nozzle and generate thrust.

The advantage of this class of rocket is that most of the mass of the matter/antimatter mixture can be converted into energy, which provides a high energy density and specific impulse that surpasses any other rocket. Moreover, the annihilation reaction can accelerate a rocket to half the speed of light.

Such a class of missiles would be the fastest and most energy efficient possible (or impossible, but proposed). Where conventional chemical rockets require tons of propellant to propel a spacecraft to its destination, an antimatter engine will do the same job with a few milligrams of propellant. The mutual annihilation of half a kilogram of hydrogen and antihydrogen particles releases more energy than a 10-megaton hydrogen bomb.

It is for this reason that NASA's Institute for Advanced Concepts is investigating this technology as a possibility for future missions to Mars. Unfortunately, when considering missions to nearby star systems, the amount of fuel needed grows exponentially and the costs become astronomical (no pun intended).

What does annihilation look like?

According to a report prepared for the 39th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, a two-stage antimatter rocket would require more than 815,000 metric tons of propellant to reach Proxima Centauri in 40 years. It's relatively fast. But the price...

While one gram of antimatter produces an incredible amount of energy, producing just one gram of antimatter would require 25 million billion kilowatt-hours of energy and cost a trillion dollars. Currently, the total amount of antimatter that has been created by humans is less than 20 nanograms.

And even if we could produce antimatter cheaply, we would need a massive ship that could hold the required amount of fuel. According to a report by Dr. Darrell Smith and Jonathan Webby of Aviation University Embry Riddle in Arizona, an antimatter-powered interstellar craft could reach 0.5 light speeds and reach Proxima Centauri in just over 8 years. However, the ship itself would weigh 400 tons and require 170 tons of antimatter fuel.

A possible way around this is to create a vessel that will create antimatter and then use it as fuel. This concept, known as the Vacuum to Antimatter Rocket Interstellar Explorer System (VARIES), was proposed by Richard Aubousi of Icarus Interstellar. Building on the idea of ​​recycling in situ, VARIES would use large lasers (powered by huge solar arrays) that create antimatter particles when fired into empty space.

Similar to the fusion ramjet concept, this proposal solves the problem of transporting fuel by extracting it directly from space. But then again, the cost of such a ship would be extremely high if built by our modern methods. We simply cannot create antimatter on a massive scale. And then there's the problem of radiation, as the annihilation of matter and antimatter produces flashes of high-energy gamma rays.

They not only pose a danger to the crew, but also to the engine, so that they do not fall apart into subatomic particles under the influence of all this radiation. In short, an antimatter drive is completely impractical given our current technology.

Alcubierre warp drive

Fans of science fiction are no doubt familiar with the concept of a warp drive (or Alcubierre drive). Proposed by Mexican physicist Miguel Alcubierre in 1994, this idea was an attempt to imagine instantaneous movement through space without disturbing special theory Einstein's relativity. In short, this concept involves the stretching of the fabric of space-time into a wave, which would theoretically cause the space in front of the object to contract and behind it to expand.

An object inside this wave (our ship) will be able to ride this wave, being in a "warp bubble", at a speed much higher than relativistic. Since the ship does not move in the bubble itself, but is carried by it, the laws of relativity and space-time will not be violated. In fact, this method does not involve faster-than-light travel in the local sense.

"Faster than light" is only in the sense that the ship can reach its destination faster than a beam of light traveling outside the warp bubble. Assuming that the spacecraft will be equipped with the Alcubierre system, it will reach Proxima Centauri in less than 4 years. Therefore, if we talk about theoretical interstellar space travel, this is by far the most promising technology in terms of speed.

Of course, this whole concept is extremely controversial. Among the arguments against, for example, is that it does not take into account quantum mechanics and can be refuted (like loop quantum gravity). Calculations of the required amount of energy also showed that the warp drive would be prohibitively gluttonous. Other uncertainties include the safety of such a system, space-time effects at the destination, and causality violations.

However, in 2012, NASA scientist Harold White said that, along with colleagues, the Alcubierre engine. White stated that they had built an interferometer that would pick up the spatial distortions produced by the expansion and contraction of the space-time of the Alcubierre metric.

In 2013, the Jet Propulsion Laboratory published the results of tests of the warp field, which were carried out in a vacuum. Unfortunately, the results were considered "inconclusive". In the long run, we may find out that the Alcubierre metric violates one or more of the fundamental laws of nature. And even if its physics turns out to be correct, there is no guarantee that the Alcubierre system can be used for flight.

In general, everything is as usual: you were born too early to travel to the nearest star. Nevertheless, if humanity feels the need to build an "interstellar ark" that will accommodate a self-sustaining human society, it will be possible to get to Proxima Centauri in a hundred years. If, of course, we want to invest in such an event.

In terms of time, all available methods seem to be extremely limited. And if spending hundreds of thousands of years traveling to the nearest star may be of little interest to us when our own survival is at stake, as space technology advances, the methods will remain extremely impractical. By the time our ark reaches the nearest star, its technology will be obsolete, and humanity itself may no longer exist.

So unless we make a major breakthrough in fusion, antimatter, or laser technology, we'll be content to study our own solar system.