On February 22, 2017, NASA announced that 7 exoplanets have been found around the single star TRAPPIST-1. Three of them are in the range of distances from the star in which the planet can have liquid water and water is the key to life. It is also reported that this star system is located at a distance of 40 light years from Earth.

This message made a lot of noise in the media, it even seemed to some that humanity was one step away from building new settlements near new star, but it's not. But 40 light-years is a lot, it's a LOT, it's too many kilometers, that is, this is a monstrously colossal distance!

From the course of physics, the third cosmic velocity is known - this is the speed that a body must have at the surface of the Earth in order to go beyond solar system. The value of this speed is 16.65 km/s. Ordinary orbiting spacecraft start at a speed of 7.9 km / s, and revolve around the Earth. In principle, a speed of 16-20 km/s is quite affordable for modern earthly technologies, but no more!

Mankind has not yet learned how to accelerate spaceships faster than 20 km/sec.

Let's calculate how many years it will take for a starship flying at a speed of 20 km/sec to overcome 40 light years and reach the star TRAPPIST-1.
One light year is the distance that a beam of light travels in a vacuum, and the speed of light is approximately 300,000 km/sec.

A human-made spacecraft flies at a speed of 20 km/sec, that is, 15,000 times slower than the speed of light. Such a ship will overcome 40 light years in a time equal to 40*15000=600000 years!

An earth ship (with the current level of technology) will fly to the star TRAPPIST-1 in about 600 thousand years! Homo sapiens exists on Earth (according to scientists) only 35-40 thousand years, and here as much as 600 thousand years!

In the near future, technology will not allow a person to reach the star TRAPPIST-1. Even promising engines (ion, photon, space sails, etc.), which are not in earthly reality, can be estimated to accelerate the ship to a speed of 10,000 km / s, which means that the flight time to the TRAPPIST-1 system will be reduced to 120 years . This is already a more or less acceptable time for flying with the help of suspended animation or for several generations of migrants, but today all these engines are fantastic.

Even the nearest stars are still too far from people, too far, not to mention the stars of our Galaxy or other galaxies.

The diameter of our galaxy Milky Way is approximately 100 thousand light years, that is, the path from end to end for a modern earthly ship will be 1.5 billion years! Science suggests that our Earth is 4.5 billion years old, and multicellular life is about 2 billion years old. The distance to the nearest galaxy to us - the Andromeda Nebula - is 2.5 million light years from Earth - what monstrous distances!

As you can see, of all people living today, no one will ever set foot on the earth of a planet near another star.

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.

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 our “nest nest”, we will have several ways to get to the nearest star system in our galaxy.

The closest star to our Earth is the Sun, quite an “average” star according to the scheme “ main sequence» Hertzsprung – Russell. 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.

In the future, if humanity wants to leave the solar system, we will have a huge selection of stars that we could go to, 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!

Reach for the star
As already noted, the closest star to our solar system is Proxima Centauri, and therefore has great sense start planning an interstellar mission from there. 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 brightest star of the three in the system, part of a tight binary system 4.37 light-years from Earth - while Proxima Centauri (the dimmest of the three) is an isolated red dwarf 0.13 light-years away from a dual system.

And although conversations about interstellar travel evoke thoughts of all sorts of "faster-than-light" (FSL) travel, ranging from warp speeds and wormholes to subspace drives, such theories either in the highest degree fictional (like the Alcubierre engine), or exist only in science fiction. Any mission to deep space will stretch over generations of people.

So, if you start with one of the slowest forms space travel how long will 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 the New Horizons mission, 16 hydrazine monopropellant thrusters 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.

From fast rocket spacecraft to economical ion propulsion, we have a couple of options for getting around in 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 ion thrusters on solar energy, in which electricity was collected by solar panels and used to power 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 thrusters take a long time to accelerate a spacecraft to substantial speeds, and top speeds depend 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 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.

On the top speed at 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 rocket fuel to last the entire 4.24 light years, the travel time will be significantly 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 relative motion(i.e. orbit) and the planet's gravity to change path and speed. Gravity maneuvers are an extremely useful technique. space flights, 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 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.

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 gravity assist, but a maximum orbital speed, but the device still holds the record for the fastest artificial 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 Helios 2's record speed - a constant speed of 240,000 km/h - it would take it 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 resonant cavity RF drive, also known as 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.

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

In 2010, Professor Zhuang Yang from Northwestern Polytechnic University in Xi'an, China, began publishing a series of articles about her 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, converting it into ionized gas (hydrogen plasma), which would then be directed into the rocket nozzle, generating thrust.

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 fusion or fission for thrust, rather than chemical fuel, on which all modern space agencies operate.

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.

Proxima Centauri.

Here's a classic backfill question. Ask your friends Which one is closest to us?" and then watch them list nearest stars. Maybe Sirius? Alpha something there? Betelgeuse? The answer is obvious - it is; 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 have probably heard that - 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 of all, 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, while Alpha Centauri B is slightly less massive than the Sun. There is also a third component in this system, a dim red dwarf Proxima Centauri (Proxima Centauri).

Proxima Centauri- That's what it is 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 only visible in the southern hemisphere. Unfortunately, even if you see this system, you will not be able to see Proxima Centauri. This star is so dim that you need a powerful enough telescope to see it.

Let's find 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 overcame this path in 2015 for 9 years. Traveling so fast to get to Proxima Centauri, New Horizons will need 78,000 light years.

Proxima Centauri is the nearest 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 distance from this star to the Earth will be only 3.11 light years. In 33,000 years, the nearest star will be Ross 248.

What about the northern hemisphere?

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

Barnard's Star.

nearest star, which you can see with the naked eye in the northern hemisphere is Sirius (Alpha Big Dog) . Sirius twice more sun in size and mass, and the brightest star in the sky. Located 8.6 light-years away in the constellation Canis Major (Canis Major), it is the most famous star chasing Orion in the night sky during the winter.

How did astronomers measure the distance to stars?

They use a method called . Let's do a little experiment. Hold one arm outstretched at length and place your finger so that some distant object is nearby. Now alternately open and close each eye. 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 with respect 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 compared to which some distant object. If the star is close to us, this angle can be measured and the distance calculated.

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

20 nearest stars

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

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

The title of the article you read "Closest Star to the Sun".

Surely, having heard in some fantastic action movie the expression a la “20 to Tatooine light years”, many asked legitimate questions. I will name some of them:

Isn't a year a time?

Then what is light year?

How many kilometers does it have?

How long will it take light year spaceship with Earth?

I decided to dedicate today's article to explaining the meaning of this unit of measurement, comparing it with our usual kilometers and demonstrating the scales that Universe.

Virtual Racer.

Imagine a person, in violation of all the rules, rushing along the highway at a speed of 250 km / h. In two hours he will overcome 500 km, and in four - as many as 1000. Unless, of course, he crashes in the process ...

It would seem that this is the speed! But in order to circumnavigate the entire globe (≈ 40,000 km), our rider will need 40 times more time. And this is already 4 x 40 = 160 hours. Or almost whole week continuous ride!

In the end, however, we will not say that he covered 40,000,000 meters. Since laziness has always forced us to invent and use shorter alternative units of measurement.

Limit.

From school course physics everyone should know that the fastest rider in universe- light. In one second, its beam covers a distance of approximately 300,000 km, and the globe, thus, it will go around in 0.134 seconds. That's 4,298,507 times faster than our virtual racer!

From Earth before Moon light reaches on average in 1.25 s, up to sun its beam will rush in a little more than 8 minutes.

Colossal, isn't it? But the existence of speeds greater than the speed of light has not yet been proven. So academia decided that it would be logical to measure cosmic scales in units that a radio wave travels over certain time intervals (which light, in particular, is).

Distances.

Thus, light year- nothing more than the distance that a ray of light overcomes in one year. On interstellar scales, using distance units smaller than this does not make much sense. And yet they are. Here are their approximate values:

1 light second ≈ 300,000 km;

1 light minute ≈ 18,000,000 km;

1 light hour ≈ 1,080,000,000 km;

1 light day ≈ 26,000,000,000 km;

1 light week ≈ 181,000,000,000 km;

1 light month ≈ 790,000,000,000 km.

And now, so that you understand where the numbers come from, let's calculate what one is equal to light year.

There are 365 days in a year, 24 hours in a day, 60 minutes in an hour, and 60 seconds in a minute. Thus, a year consists of 365 x 24 x 60 x 60 = 31,536,000 seconds. Light travels 300,000 km in one second. Consequently, in a year its beam will cover a distance of 31,536,000 x 300,000 = 9,460,800,000,000 km.

This number reads like this: NINE TRILLION, FOUR HUNDRED SIXTY BILLION AND EIGHT HUNDRED MILLION kilometers.

Of course, the exact value light year slightly different from what we calculated. But when describing distances to stars in popular science articles, in principle, the highest accuracy is not needed, and a hundred or two million kilometers will not play a special role here.

Now let's continue our thought experiments...

Scales.

Let's assume modern spaceship leaves solar system from the third space speed(≈ 16.7 km/s). First light year he will overcome in 18,000 years!

4,36 light years to our nearest star system ( Alpha Centauri, see the image at the beginning) it will overcome in about 78 thousand years!

Our the Milky Way galaxy, having a diameter of approximately 100,000 light years, it will cross in 1 billion 780 million years.

Astronomers have discovered the first potentially habitable planet outside the solar system.

The reason for this conclusion is the work of American "exoplanet hunters" (exoplanets are those that revolve around other stars, not around the Sun).

It is published by the Astrophysical Journal. The publication can be found at arXiv.org.

The red dwarf Gliese-581, which, when viewed from Earth, is located in the constellation Libra at a distance of 20.5 light years (one light year = the distance that light travels in a year at a speed of 300 thousand km / s.), Has long attracted to the attention of "exoplanet hunters".

It is known that among the exoplanets discovered so far, most are very massive and similar to Jupiter - they are easier to find.

In April last year, a planet was found in the Gliese-581 system, which at that time became the lightest planet known. solar planets outside the solar system, revolving around stars similar in parameters to the Sun.

The planet Gliese-581e (fourth in that system) turned out to be only 1.9 times more massive than Earth.

This planet revolves around its star in just 3 (Earth) days and 4 hours.

Now scientists are reporting the discovery of two more planets in this star system. Of greatest interest is the discovered sixth planet - Gliese-581g.

It is her astronomers who call the first habitable.

Using their own and archival data from the Keck Telescope, which is based in the Hawaiian Islands, the researchers measured the parameters of this planet and came to the conclusion that there may be an atmosphere and water in liquid form.

So, scientists have found that this planet has a radius of 1.2 to 1.5 Earth radii, a mass of 3.1 to 4.3 Earth masses and a period of revolution around its star of 36.6 Earth days. Major axis elliptical orbit this planet is about 0.146 astronomical units (1 astronomical unit is the average distance between the Earth and the Sun, which is approximately equal to 146.9 million km).

The acceleration of free fall on the surface of this planet exceeds a similar parameter for the Earth by 1.1-1.7 times.

As for the temperature regime on the surface of Gliese-581g, according to scientists, it ranges from -31 to -12 degrees Celsius.

And although for a simple layman this range cannot be called anything other than frosty, on Earth life exists in a much wider range from -70 in Antarctica to 113 degrees Celsius in geothermal sources where microorganisms live.

Since the planet is close enough to its star, there is a high probability that Gliese-581g, due to tidal forces, is always turned to its luminary on one side, just as the Moon “looks” at the Earth all the time with only one of its hemispheres.

The fact that in less than 20 years astronomers have gone from discovering the first planet around other stars to potentially habitable planets indicates, according to the authors of the sensational work, that there are many more such planets than previously thought.

And even our Milky Way galaxy may be teeming with potentially habitable planets.

It took more than 200 measurements to detect this planet, with an accuracy of, for example, a speed of 1.6 m / s.

Since hundreds of billions of stars are sheltering in our galaxy, scientists conclude that tens of billions of them have potentially habitable planets.