Proxima Centauri.

Here's a classic backfill question. Ask your friends, " Which one is the closest to us?"and then watch how they list nearby stars... Maybe Sirius? Alpha is there something? Betelgeuse? The obvious answer is this; a massive ball of plasma located about 150 million kilometers from Earth. Let's clarify the question. Which star is closest to the Sun?

Nearest star

You've probably heard that it is the third brightest star in the sky at a distance of only 4.37 light years from. But Alpha Centauri not a single star, it is a system of three stars. First, a double star (binary star) with a common center of gravity and an orbital period of 80 years. Alpha Centauri A is only slightly more massive and brighter than the Sun, and Alpha Centauri B is slightly less massive than the Sun. This system also contains a third component, a dull red dwarf Proxima Centauri.

Proxima Centauri- That's what it is the closest star to our sun located at a distance of only 4.24 light years.

Proxima Centauri.

Multiple star system Alpha Centauri located in the constellation Centaurus, which is visible only in the southern hemisphere. Unfortunately, even if you see this system, you will not be able to see Proximu Centauri... This star is so faint that you need a powerful enough telescope to see it.

Let's figure out the scale of how far Proxima Centauri from U.S. Think about. moves at a speed of almost 60,000 km / h, the fastest in. He covered this path in 2015 in 9 years. Traveling fast enough to get to Proxima Centauri, New Horizons will take 78,000 light years.

Proxima Centauri is the closest star over 32,000 light years, and it will hold this record for another 33,000 years. It will make its closest approach to the Sun in about 26,700 years, when the star is only 3.11 light years away from Earth. In 33,000 years, the nearest star will be Ross 248.

What about the northern hemisphere?

For those of us in the northern hemisphere, the closest visible star is Barnard's Star, another red dwarf in the constellation Ophiuchus. Unfortunately, like Proxima Centauri, Barnard's Star is too dim to see with the naked eye.

Barnard's Star.

Nearest star that you can see with the naked eye in the northern hemisphere is Sirius (Alpha Canis Major)... Sirius is twice the size and mass of the Sun and is the brightest star in the sky. Located 8.6 light years away in the constellation Canis Major, it is the most famous star that stalks Orion in the night sky in winter.

How did astronomers measure the distance to the stars?

They use a method called. Let's do a little experiment. Keep one arm outstretched and place your finger so that there is some distant object nearby. Now open and close each eye in turn. Notice how your finger seems to jump back and forth when you look with different eyes. This is the parallax method.

Parallax.

To measure the distance to the stars, you can measure the angle to the star in relation to when the Earth is on one side of the orbit, say in the summer, then 6 months later, when the Earth moves to the opposite side of the orbit, and then measure the angle to the star relative to what - any distant object. If the star is close to us, this angle can be measured and the distance calculated.

You can actually measure the distance in this way up to nearby stars but this method only works up to 100 "000 light years.

20 closest stars

Here is a list of the 20 closest star systems and their distance in light years. Some of them have multiple stars, but they are part of the same system.

According to NASA, there are 45 stars within a 17 light-year radius of the Sun. There are over 200 billion stars in the world. Some are so dim that they are nearly impossible to detect. Perhaps with new technologies, scientists will find stars even closer to us.

Title of the article you read "The closest star to the Sun".

With the telescopes of the European Southern Observatory (ESO), astronomers have made another surprising discovery. This time, they found accurate evidence of the existence of an exoplanet orbiting around the star closest to Earth - Proxima Centauri. The world, called Proxima Centauri b (Proxima Centauri b), has long been searched for by scientists all over the Earth. Now, thanks to his discovery, it has been established that the period of its revolution around its native star (year) is 11 Earth days, and the surface temperature of this exoplanet is suitable for the possibility of finding water in liquid form. By itself, this stone world is slightly larger than the Earth and, like the star, has become the closest to us of all such space objects. In addition, this is not just the closest exoplanet to Earth, it is also the closest world suitable for the existence of life.

Proxima Centauri is a red dwarf, and it is located at a distance of 4.25 light years from us. The star received its name for a reason - this is another confirmation of its proximity to the Earth, since proxima is translated from Latin as “closest”. This star is located in the constellation Centaurus, and its luminosity is so weak that it is completely impossible to see it with the naked eye, and besides, it is quite close to the much brighter pair of stars α Centaurus AB.

During the first half of 2016, Proxima Centauri was regularly surveyed using the HARPS spectrograph installed on the 3.6-meter telescope in Chile, as well as simultaneously with other telescopes from around the world. The star was studied as part of the Pale Red Dot campaign, during which scientists from the University of London studied the oscillations of the star caused by the presence of an unidentified exoplanet in its orbit. The name of this program is a direct reference to the famous image of the Earth from the far reaches of the Solar System. Then Carl Sagan called this picture (blue speck). Since Proxima Centauri is a red dwarf, the name of the program has been corrected.

Since this topic of exoplanet search has generated wide public interest, the progress of scientists in this work from mid-January to April 2016 was consistently publicized on the program's own website and via social media. These reports were accompanied by numerous articles written by experts from all over the world.

“We received the first hints of the possibility of the existence of an exoplanet here, but our data then turned out to be inconclusive. Since then, we have worked hard to improve our observations with the help of the European Observatory and other organizations. For example, the planning of this campaign took approximately two years. ”- Guillem Anglada-Escudé, Research Team Leader.

Pale Red Dot data, combined with earlier observations from ESO and others, showed a clear signal of the presence of an exoplanet. It was very accurately established that from time to time Proxima Centauri approaches the Earth at a speed of 5 kilometers per hour, which is equal to the usual human speed, and then moves away at the same speed. This regular cycle of radial velocity changes repeats with a period of 11.2 days. A careful analysis of the resulting Doppler shifts indicated the presence of a planet with a mass of at least 1.3 times that of Earth at a distance of 7 million kilometers from Proxima Centauri, which is only 5 percent of the distance from Earth to the Sun. In general, such a detection has become technically possible only in the last 10 years. But, in fact, signals with even lower amplitudes were detected earlier. However, stars are not smooth balls of gas, and Proxima Centauri is a very active star. Therefore, accurately detecting Proxima Centauri b became possible only after obtaining a detailed description of how the star changes on time scales from minutes to decades, and monitoring its luminosity with light-measuring telescopes.

“We continued to check the data to ensure that the signal we received did not contradict what we found. This was done every day for another 60 days. After the first ten days we gained confidence, after 20 days we realized that our signal was in line with expectations, and after 30 days all the data categorically asserted the discovery of the exoplanet Proxima Centauri b, so we began to prepare articles on this event. ”

Red dwarfs like Proxima Centauri are active stars and have many tricks in their arsenal to mimic the presence of an exoplanet in their orbits. To eliminate this error, the researchers monitored the change in the star's brightness using the ASH2 telescope at the San Pedro de Atacami Observatory in Chile and the Las Cumbres Observatory telescope network. Radial velocity information as the star increased in luminosity was excluded from the final analysis.

Despite the fact that Proxima Centauri b orbits much closer to its star than Mercury around the Sun, Proxima Centauri itself is much weaker than our star. As a result, the discovered exoplanet is located exactly in the region around the star, suitable for the existence of life in the form in which we know it, and the estimated temperature of its surface allows water to be present in liquid form. Despite such a moderate orbit, the conditions of existence on its surface can be very strongly influenced by ultraviolet radiation and X-ray flares from the star, which are much more intense than the effects that the Sun has on the Earth.

The actual ability of this kind of planet to support liquid water and have life similar to Earth is a matter of intense but mainly theoretical debate. The main arguments that speak against the presence of life relate to the proximity of Proxima Centauri. For example, on Proxima Centauri b, such conditions can be created under which it is always facing the star with one side, which is why on one half it is eternal night, and on the other it is eternal day. The planet's atmosphere could also slowly evaporate or have more complex chemistry than Earth's due to strong ultraviolet and X-ray radiation, especially during the star's first billion years. However, until now, not a single argument has been proven conclusively, and they are unlikely to be eliminated without direct observational evidence and obtaining accurate characteristics of the planet's atmosphere.

Two separate works were devoted to the habitability of Proxima Centauri b and its climate. It has been established that today it is impossible to exclude the existence of liquid water on the planet, and in this case it can be present on the planet's surface only in the sunniest regions, either in the region of the planet's hemisphere, always facing the star (synchronous rotation), or in the tropical belt (3: 2 resonant rotation). The rapid movement of Proxima Centauri b around the star, the strong radiation of Proxima Centauri and the history of the formation of the planet made the climate on it completely different from that on Earth, and it is unlikely that Proxima Centauri b has seasons at all.

Either way, this discovery will mark the beginning of large-scale follow-up observations, both with current instruments and the next generation of giant telescopes such as the European Extremely Large Telescope (E-ELT). In subsequent years, Proxima Centauri b will become the main target for the search for life elsewhere in the universe. This is quite symbolic, since the Alpha Centauri system was also chosen as the goal of the first attempt of mankind to move to another star system. The Breakthrough Starshot Project is a research and engineering project under the Breakthrough Initiatives program to develop a concept for a fleet of lightsail-powered spaceships called the StarChip. This type of spacecraft will be able to travel to the Alpha Centauri star system, 4.37 light years from Earth, at a speed of between 20 and 15 percent of the speed of light, which will take 20 to 30 years, respectively, and another 4 years to notify Earth of a successful arrival.

In conclusion, I would like to note that many accurate methods for searching for exoplanets are based on the analysis of its passage through the disk of a star and starlight through its atmosphere. There is currently no evidence that Proxima Centauri b is traversing the parent star, and opportunities to see this event are currently negligible. However, scientists hope that in the future, the effectiveness of observing instruments will increase.

> 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. Located in the constellation Centaurus. The distance from the 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.

It is believed that Proxima Centauri is the third member of the Alpha Centauri AB system, but its orbital period reaches 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. In 1915, Robert Innes found her.

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

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

The Hubble Telescope was able to capture the bright glow of the nearest star - Proxima Centauri. Located in the constellation Centaurus, 4 light years away. It looks 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, convection processes inside it lead to random changes in luminosity. It also hints at the star's continued existence. Scientists believe it will remain in the main sequence for another 4 trillion years, 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, not in the frame.

It is believed that as a result, Proxima Centauri will begin to cool down and shrink, 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 transforms into a white dwarf.

The star can be observed by those who live south of 27 ° N. NS. A minimum of 3.1-inch telescope and ideal viewing conditions are required to view.

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 will take its place - it is a red dwarf located in the constellation Andromeda.

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

Proxima Centauri is the closest star to Earth

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

These are huge distances. The Voyager 1 spacecraft moves at a speed of 17.3 km / s (faster than a bullet). If he headed for the star Proxima Centauri, it would take 73,000 years to travel. If I 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 repeated measurements after 6 months, when the Earth was on the other side of the orbit. Although Proxima Centauri is the closest, it is believed that unnoticed brown dwarfs may still be located between us and the star.

A detailed review of the system has removed superterrestrial planets and brown dwarfs from the habitable zone. Proxima Centauri is an explosive stellar type, so it may not support life at all on potential planets. Any worlds in orbit around the star can be found with the James Webb Telescope, scheduled to launch in 2021.

Proxima Centauri Star Facts

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

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

The flaring nature of the star was noted by Harlow Shapley in 1951. If we compare it with archived images, we can see that its value increased by 8%. This helped Proxima Centauri to become the most active flare star.

Proxima Centauri belongs to the M5.5 class - it is a red dwarf with an extremely low mass. Because of this, its inner part is convective, where helium circulates throughout the star, and does not accumulate 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% of the solar, and the surface temperature rises to 3500 K. The star will perform the 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 constellation of 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 distant from stars. At the same time, the star spends 500,000 years in orbit. Most likely, there is a gravitational connection between them.

A three-component system in the constellation Centaurus forms when a low-mass star is attracted by a more massive binary system within the cluster before it dissipates. Alpha Centauri and Proxima Centauri share a common correct motion with triple, two double, and six single stars. This suggests that all of 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 indicating the Southern Cross asterism. The binary star system can be resolved with a small telescope. But Proxima Centauri is 2 degrees south, and at least a large amateur telescope is needed 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 magnitude: 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.
• Rotational 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.

At some point in our lives, each of us asked this question: how long to fly to the stars? Is it possible to carry out such a flight in one human life, can such flights become the norm of everyday life? There are many answers to this difficult question, depending on who is asking. Some are simple, others are more difficult. To find a definitive answer, there is too much to take into account.

The answer to this question is not so simple.

Unfortunately, no real estimates exist that would help find such an answer, and this is frustrating for futurists and interstellar travel enthusiasts. Whether we like it or not, space is very large (and complex) and our technology is still limited. But if we ever decide to leave our "home 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 there are other planets orbiting the 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? Keep in mind that this is all speculation and there are no landmarks 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 with it. Part of the Alpha Centauri triple star system, Proxima is 4.24 light years (1.3 parsecs) from Earth. Alpha Centauri is essentially the brightest star of the three in the system, part of a close binary system 4.37 light years from Earth - while Proxima Centauri (the faintest of the three) is an isolated red dwarf 0.13 light years away. from a dual system.

And while conversations about interstellar travel suggest all kinds of faster-than-light travel (FSS), from warp speeds and wormholes to subspace engines, such theories are either highly fictional (sort of) or only exist in science fiction. Any mission to deep space will stretch 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 assessing the duration of travel in space is much easier if existing technologies and bodies in our solar system are involved in it. For example, using the technology used, 16 engines powered by hydrazine monofuel, you can reach the Moon in just 8 hours and 35 minutes.

There is also the European Space Agency's SMART-1 mission, which was propelled towards the Moon using ion thrust. With this revolutionary technology, a variant of which the Dawn space probe also used to reach Vesta, it took SMART-1 a year, a month and two weeks to reach the Moon.

Ion thrust engine

From a fast rocket spacecraft to an economical ion drive, we have a couple of options for getting around local space - plus you could use Jupiter or Saturn as a giant gravity slingshot. Nevertheless, if we plan to get a little further, we will have to build up the power of technology and explore new possibilities.

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

Ionic movement

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

SMART-1 used solar ion thrusters, in which electricity was collected by solar panels and used to power Hall effect thrusters. 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 effective form of movement, but far from the fastest.

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

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

Therefore, if ion propulsion is used in a mission to Proxima Centauri, the engines must have a powerful source of energy (nuclear power) and large reserves of fuel (although less than conventional rockets). But if we 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), calculations can be made.

At a top speed of 56,000 km / h, Deep Space 1 would take 81,000 years to travel 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 will be too slow for a manned interstellar mission.

But if the ion thrusters are larger and more powerful (that is, the rate of exit of the ions will be significantly higher), if there is enough rocket fuel, which is enough for the entire 4.24 light years, travel time will be significantly reduced. But all the same there will be much longer than the period of human life.

Gravity maneuver

The fastest way to travel in space is to use gravity assist. This method involves the spacecraft using the relative motion (i.e. orbit) and gravity of the planet to alter its path and speed. Gravitational maneuvers are an extremely useful technique for space flight, especially when using 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 toward 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. That is, from the Sun, the record for the highest speed developed using a gravitational maneuver holds. 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.

Helios mission

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

If Voyager 1 was 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 that 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. Much better, although not nearly practical.

Electromagnetic motor EM Drive

Another proposed method for interstellar travel is also known as EM Drive. Proposed back in 2001 by Roger Scheuer, a British scientist who created Satellite Propulsion Research Ltd (SPR) to implement the project, the engine is based on the idea that electromagnetic microwave cavities can directly convert electricity into thrust.

EM Drive - resonant cavity motor

Whereas traditional electromagnetic motors are designed to propel a specific mass (such as ionized particles), this particular propulsion system does not depend on the reaction of the mass and does not emit directional radiation. In general, this engine was greeted 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 under the action of force.

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

In April 2015, scientists at NASA Eagleworks (part of the Johnson Space Center) said they had successfully tested the engine in a vacuum, which could indicate a possible use in space. In July of that year, a group of scientists from the space systems department of the Dresden University of Technology developed their own version of the engine and observed tangible thrust.

In 2010, Professor Zhuang Yang of Northwestern Polytechnic University in Xi'an, China, began publishing a series of articles about her research on EM Drive technology. In 2012, it reported a high input power (2.5 kW) and a fixed thrust of 720 mn. In 2014, she also performed extensive tests, including internal temperature measurements with built-in thermocouples, which showed that the system was working.

According to calculations based on the NASA prototype (which was given a power rating of 0.4 N / kilowatt), an electromagnetic-powered spacecraft could make a trip to Pluto in less than 18 months. This is six times less than what was required by the New Horizons probe, which was moving at a speed of 58,000 km / h.

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 points are dotted over it in this technology, it is too early to talk about its use.

Nuclear thermal and nuclear electric propulsion

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

Nuclear powered rockets

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

Compared to chemical engines, nuclear engines have undeniable advantages. Firstly, it is practically unlimited energy density compared to rocket fuel. In addition, the nuclear engine will also generate powerful thrust relative to the amount of fuel being used. This will reduce the amount of fuel required, and at the same time the weight and cost of a particular apparatus.

Although thermal nuclear power engines have not yet entered 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 fission or fusion, NASA scientists could deliver a spacecraft to Mars in just 90 days if the Red Planet is 55,000,000 kilometers from Earth.

But when it comes to travel to Proxima Centauri, a nuclear rocket will take centuries to accelerate to a substantial fraction of the speed of light. Then it will take several decades of the way, and behind them many more centuries of inhibition on the way to the goal. We are still 1000 years from our destination. What's good for interplanetary missions, not so good for interstellar missions.

Nuclear power plant

A nuclear power plant is a theoretically possible "engine" for fast space travel. The concept was originally proposed by Stanislaw Ulam in 1946, a Polish-American mathematician who participated, and preliminary calculations were made by F. Reines and Ulam in 1947. The Orion project was launched in 1958 and existed until 1963.

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

Orion was supposed to use the power of pulsed nuclear explosions

In a nutshell, Project Orion includes a large spacecraft that picks up speed by supporting thermonuclear warheads, throwing bombs behind and accelerating by a blast wave that travels into a rear-mounted pusher, a propellant panel. After each push, the force of the explosion is absorbed by this panel and converted into forward motion.

Although this design is hardly elegant by modern standards, the advantage of the concept is that it provides a high specific thrust - that is, it extracts the maximum amount of energy from a fuel source (in this case, nuclear bombs) at the lowest cost. In addition, this concept can theoretically accelerate very high speeds, according to some estimates, up to 5% of the speed of light (5.4 x 10 7 km / h).

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

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

There is also a small problem of radiation that it will emit, not to mention nuclear waste. It is believed that it is for this reason that 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 generate thrust. Under this concept, energy must be created by inertial confinement igniting pellets of a mixture of deuterium and helium-3 in a reaction chamber using electron beams (similar to what is done at the National Ignition Complex in California). Such a fusion reactor would detonate 250 pellets per second, creating high-energy plasma, which would then be redirected into a nozzle, creating thrust.

The Daedalus project 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. The estimated speed should reach 10,600 km / h, well above the speed limits of conventional rockets. Moreover, this technology has been actively studied over the past several decades, and many proposals have been made.

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

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

Agree, it looks very nice!

Project Daedalus estimates that it would have taken the mission 50 years to reach Barnard's Star. If to Proxima Centauri, the same ship will reach in 36 years. But, of course, the project includes a lot of unresolved issues, in particular unsolvable with the use of modern technologies - and most of them have not yet been resolved.

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 propels the apparatus requires that the energy emitted be much greater than the energy expended to trigger 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, there remains the question of the cost of such a vessel. Even by the modest standards of a Project Daedalus unmanned vehicle, a fully equipped vehicle would weigh 60,000 tons. Just so you know, the gross weight of the NASA SLS is just over 30 metric tons, and the launch alone will cost $ 5 billion (2013 estimates).

In short, a fusion rocket will not only be too expensive to build, but it will also require a fusion reactor level far beyond our capabilities. Icarus Interstellar, an international organization of civilian scientists (some of whom have worked for NASA or ESA), is trying to revitalize the concept with Project Icarus. Gathered in 2009, the group hopes to make the fusion movement (and others) possible for the foreseeable future.

Thermonuclear ramjet engine

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

As the vehicle picks up speed, the reactive mass enters the confining magnetic field, which compresses it before the start of thermonuclear fusion. The magnetic field then directs energy into the rocket nozzle, accelerating the ship. Since no fuel tanks will slow it down, a thermonuclear ramjet can reach speeds of the order of 4% light and go anywhere in the galaxy.

However, this mission has many possible disadvantages. For example, the problem of friction. The spacecraft relies on high fuel collection rates, but it will also collide with large amounts 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 not yet under our control.

However, science fiction has grown to love this concept. The most famous example is perhaps the Star Trek franchise, which uses the Bussard Collectors. In reality, our understanding of fusion reactors is nowhere near as perfect as we would like.

Laser sail

Solar sails have long been considered an effective way to conquer 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 rockets that need fuel, the sail uses the pressure of the stars' radiation to propel ultra-thin mirrors to high speeds.

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

What is there in space? That's right - sunlight

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

According to a 2000 study by Robert Frisbee, director of advanced propulsion research at NASA's Jet Propulsion Laboratory, a laser sail would hit 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, a sail of 965 kilometers in diameter will arrive 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, lasers will need a steady stream of 17,000 terawatts of energy - roughly how much the entire world consumes in one day.

Antimatter engine

Science fiction lovers are well aware of what antimatter is. But if you forget, antimatter is a substance made up of particles that have the same mass as ordinary particles, but the opposite charge. Antimatter engine is a hypothetical engine that relies on interactions between matter and antimatter to generate energy, or create thrust.

Hypothetical antimatter engine

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

The advantage of this class of rockets 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 is superior to any other rocket. Moreover, the annihilation reaction can accelerate the rocket to half the speed of light.

This class of missiles will be the fastest and most energy efficient possible (or impossible, but proposed). If conventional chemical rockets require tons of fuel to propel a spacecraft to its destination, an antimatter engine will do the same job using a few milligrams of fuel. Mutual destruction 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 Advanced Concepts Institute is investigating this technology as possible for future missions to Mars. Unfortunately, when looking at missions to nearby star systems, the amount of fuel needed grows exponentially, and the costs become astronomical (and this is not a pun).

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 will require more than 815,000 metric tons of fuel to reach Proxima Centauri in 40 years. It's relatively fast. But the price ...

Although one gram of antimatter produces an incredible amount of energy, producing one gram alone would require 25 million billion kilowatt-hours of energy and would 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 Embry-Riddle Aviation University in Arizona, an antimatter-powered interstellar spacecraft could pick up 0.5 light speed and reach Proxima Centauri in a little over 8 years. Nevertheless, the ship itself would weigh 400 tons and would 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 Obausi of Icarus Interstellar. Building on the idea of ​​on-site reprocessing, VARIES would use large lasers (powered by huge solar panels) to create antimatter particles when fired into empty space.

Like the concept with a thermonuclear ramjet engine, this proposal solves the problem of transporting fuel by extracting it directly from space. But again, the cost of such a ship will be extremely high if built with our modern methods. We simply cannot create antimatter on a massive scale. The radiation problem also needs to be addressed, since the annihilation of matter and antimatter produces bursts of high-energy gamma rays.

They not only pose a threat 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 engine is completely impractical with our current technology.

Alcubierre Warp Drive

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

An object inside this wave (our ship) will be able to ride on this wave, being in a "warp bubble", at a speed much higher than the relativistic one. 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 movement faster than the speed of light in the local sense.

It is "faster than light" only in the sense that the ship can reach its destination faster than a ray of light traveling outside the warp bubble. Assuming the spacecraft is 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. Arguments against, for example, are that it does not take quantum mechanics into account and can be refuted (like loop quantum gravity). Calculations of the required amount of energy also showed that the warp drive would be prohibitively voracious. Other uncertainties include the safety of such a system, the effects of spacetime at the destination, and violations of causality.

However, in 2012, NASA scientist Harold White said that, together with his colleagues, the Alcubierre engine. White stated that they had built an interferometer that would capture the spatial distortions produced by the expansion and contraction of the spacetime of the Alcubierre metric.

In 2013, the Jet Propulsion Laboratory published the results of warp field tests, which were carried out under vacuum conditions. Unfortunately, the results were considered “inconclusive”. In the long run, we can find out that the Alcubierre metric violates one or more 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 house a self-sustaining human society, it will take a hundred years to get to Proxima Centauri. If, of course, we want to invest in such an event.

In terms of time, all the available methods seem extremely limited. And if we spend hundreds of thousands of years traveling to the nearest star, we may be of little interest, 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 technologies will become 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 with exploring our own solar system.

Alpha Centauri is the target of spacecraft in many science fiction novels. This closest star to us refers to a celestial drawing that embodies the legendary centaur Chiron, according to Greek mythology, the former teacher of Hercules and Achilles.

Modern researchers, like writers, tirelessly return in their thoughts to this star system, since it is not only the first candidate for a long 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, and similar stars are characterized by a close arrangement of two components and a distant third. Proxima is 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.

Sunny relatives

Alpha Centauri A and B differ from the companion not only in the distance to 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. It can be clearly seen from Earth, since it has a magnitude of zero. This parameter makes it the fourth in the list of the brightest points in the night sky. The size of the object is almost the same as that of the sun.

The star Alpha Centauri B is inferior to our star in mass (approximately 0.9 of the values ​​of the corresponding parameter of the Sun). It belongs to 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 from each other than the Earth is from the Sun. Toliman A and Toliman B revolve together 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 presumably existing 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 the star. The distance does not allow direct observation of the planets. Obtaining evidence of the existence of a land-like object became possible only with the improvement of technology.

Using the method of radial velocities, scientists were able to detect very small oscillations of Toliman B, arising under the influence of the gravitational forces of the planet rotating around him. Thus, evidence was obtained for the existence of at least one such object in the system. The vibrations caused by the planet are manifested in the form of its displacement 51 cm per second forward and then backward. In the conditions of the Earth, such a movement of even 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 orbits Alpha Centauri B in 3.2 days. It is located very close to the star: the orbital radius is ten times less 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: close 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 up too much.

Nearest

The third component that makes the whole 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 is the eleventh red dwarf object, small (about 7 times smaller than the Sun) and very faint. It is impossible to see him with the naked eye. Proxima is characterized by a "restless" state: a star is capable of doubling its brightness in a few minutes. The reason for this "behavior" in the internal processes occurring in the bowels of the dwarf.

Ambivalent 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, recently 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 doubts was the data, which stated that a close-knit pair of stars did not have sufficient attraction to also hold Proxima. The information received in the early 90s of the last century needed additional confirmation for a long time. Recent observations and calculations of scientists have not given an unambiguous answer. According to assumptions, Proxima can still be part of a triple system and move around a common gravitational center. Moreover, its orbit should resemble an elongated oval, and the most distant point from the center is the one in which the star is now observed.

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, therefore scientists are actively looking for options for its reduction.

A group of NASA researchers led by Harold White is developing the "Speed" project, the result of which should be a new engine. Its feature will be the ability to overcome the speed of light, due to which the flight from Earth to the nearest star will be only two weeks. Such a miracle of technology will become a real masterpiece of the cohesive work of theoretical physicists and experimentalists. 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 become a reality no earlier than two hundred years later. A reduction in the period is possible only if a discovery is made that can radically change the existing ideas about space flights.

Right now, Proxima Centauri and her companions remain an ambitious target, unattainable in the near future. Technique, however, is constantly being improved, and new information about the characteristics of the stellar system is clear evidence of this. Already today scientists can do a lot of things that 40-50 years ago they could not have dreamed of.