|
|
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, a binary 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 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, this 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. | Star | Distance, St. years |
| Alpha Centauri | 4,2
|
| Barnard's Star | 5,9
|
| Wolf 359 (Wolf 359; CN Lion) | 7,8
|
| Lalande 21185 (Lalande 21185) | 8,3
|
| Sirius | 8,6
|
| Leuthen 726-8 (Luyten 726-8) | 8,7
|
| Ross 154 (Ross 154) | 9,7
|
| Ross 248 (Ross 248 | 10,3
|
| Epsilon Eridani | 10,5
|
| Lacaille 9352 (Lacaille 9352) | 10,7
|
| Ross 128 (Ross 128) | 10,9
|
| EZ Aquarii (EZ Aquarii) | 11,3
|
| Procyon (Procyon) | 11,4
|
| 61 Cygni | 11,4
|
| Struve 2398 (Struve 2398) | 11,5
|
| Groombridge 34 (Groombridge 34) | 11,6
|
| Epsilon Indi | 11,8
|
| DX Cancri | 11,8
|
| Tau Ceti | 11,9
|
| GJ 106 | 11,9
|
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 space ship 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 a whole week of continuous driving!
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 a school physics course, 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. Therefore, the scientific world decided that it would be logical to measure cosmic scales in units that a radio wave passes over certain time intervals (which light, in particular, is).
Distances.
In this way, 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, the highest accuracy is in principle 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 with the third space velocity (≈ 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.
And how many potentially explosive stars are located at an unsafe distance?
A supernova is an incredible explosion of a star - and almost beyond the limits of human imagination. If our Sun were to explode as a supernova, the resulting shock wave would probably not destroy the entire Earth, but the side of the Earth facing the Sun would disappear. Scientists believe that the temperature of the planet as a whole would increase by about 15 times. Moreover, the Earth will not remain in orbit.
A sudden decrease in the mass of the Sun could free the planet and send it wandering into space. It is clear that the distance to the Sun - 8 light minutes - is not safe. Fortunately, our Sun is not a star destined to explode in a supernova. But other stars, outside our solar system, might. What is the closest safe distance? Scientific literature shows 50 to 100 light years as the closest safe distance between Earth and a supernova.
Optical image of the remnant of supernova 1987A, taken by the Hubble Space Telescope
What happens if a supernova explodes near the Earth? Let's consider the explosion of a star other than our Sun, but still at an unsafe distance. Let's say a supernova is 30 light years away. Dr. Mark Reid, senior astronomer at the Harvard-Smithsonian Center for Astrophysics, says:
“... if there was a supernova that was about 30 light years away, it would lead to strong impacts on the Earth, possibly mass extinctions. X-rays and more energetic gamma rays from a supernova can destroy the ozone layer that protects us from the sun's ultraviolet rays. It could also ionize nitrogen and oxygen in the atmosphere, leading to the formation of large amounts of nitrous oxide-like smog in the atmosphere."
Moreover, if a supernova were to explode 30 light years away, phytoplankton and reef communities would be particularly affected. Such an event severely depletes the base of the ocean food chain.
Let's assume that the explosion was a little more distant. The explosion of a nearby star could leave Earth, its surface, and ocean life relatively untouched. But any relatively close explosion would still "douse" us with gamma rays and other high-energy particles. This radiation can cause mutations in earthly life. In addition, the radiation of the nearest supernova could change our climate.
It is known that a supernova has not exploded at such a close distance in the known history of mankind. The most recent supernova visible to the eye was supernova 1987A, in 1987. It was about 168,000 light years away. Prior to this, the last flash visible to the eye was recorded by Johannes Kepler in 1604. Approximately 20,000 light years away, it shone brighter than any star in the night sky. This explosion was visible even in daylight! As far as we know, this did not cause noticeable consequences.
How many potential supernovae are closer to us than 50 to 100 light years away? The answer depends on the type of supernova. A Type II supernova is an aging massive star that is collapsing. There are no stars massive enough to do this within 50 light-years of Earth.
But there are also Type I supernovae - caused by the collapse of a small, pale white dwarf star. These stars are dim and hard to spot, so we can't be sure how many there are around. Probably several hundred of these stars are within 50 light years.
Relative sizes of IK Pegasi A (left), B (bottom, center) and the Sun (right). The star IK Pegasi B is the closest candidate for the role of a supernova prototype. It is part of a binary star system located about 150 light years from our Sun and solar system.
The main star in the system, IK Pegasi A, is an ordinary main sequence star not unlike our Sun. A potential Type I supernova is another star, IK Pegasi B, a massive white dwarf that is extremely small and dense. When star A begins to evolve into a red giant, it is expected to grow to a radius where it will collide with a white dwarf or start pulling matter from A's expanded gas envelope. When star B becomes massive enough, it can explode as a supernova.
What about Betelgeuse? Another star often mentioned in the history of supernovae is Betelgeuse, one of the brightest stars in our sky, part of the famous constellation Orion. Betelgeuse is a supergiant star. It is inherently very bright.
However, this brilliance comes at a price. Betelgeuse is one of the most famous stars in the sky because it will explode someday. The enormous energy of Betelgeuse requires that the fuel be used up quickly (relatively speaking), and in fact Betelgeuse is already nearing the end of its life. Someday soon (astronomically speaking) it will run out of fuel and then experience a spectacular Type II supernova explosion. When this happens, Betelgeuse will become brighter for weeks or months, perhaps as bright as the full moon and visible in broad daylight.
When will it happen? Probably not in our lives, but no one knows for sure. It could be tomorrow or a million years in the future. When this happens, everyone on Earth will witness an impressive event in the night sky, but earthly life will not be affected. This is because Betelgeuse is 430 light years away.
How often do supernovae break out in our galaxy? Nobody knows. Scientists have suggested that high-energy supernova radiation has already caused mutations in terrestrial species, maybe even humans.
According to one estimate, there may be one dangerous supernova event in the vicinity of the Earth every 15 million years. Other scientists say that, on average, a supernova explosion occurs within 10 parsecs (33 light years) of Earth every 240 million years. So you see what we really don't know. But you can compare those numbers to a few million years—the time humans are thought to have existed on the planet—and four and a half billion years for the very age of the Earth.
And, if you do, you will see that a supernova is sure to explode near the Earth - but probably not in the foreseeable future of mankind.
Like( 3
)
I do not like( 0
)
The light year is known to many from fantastic. Despite the fact that its name is similar to the time period of the year, the year does not measure time at all, but distance. This unit is designed to measure huge.
A light year is a non-systemic unit of length. This is the distance that light travels in a vacuum in one year (365.25 days or 31,557,600 seconds).
The comparison of a light year with a calendar year began to be used after 1984. Before that, a light year is the distance traveled by light in one tropical year.
The length of the tropical year does not have an exact value, since its calculations are related to the angular velocity of the Sun, and there are variations for it. For a light year, an average value was taken.
The difference in calculation between a tropical light year and a Julian light year is 0.02 percent. And since this unit is not used for high-precision measurements, there is no practical difference between them.
The light year as a length is used in popular science literature. In astronomy, there is another off-system unit for measuring large distances - the parsec. The calculation of the parsec is based on the average radius of the earth's orbit. 1 parsec is equal to 3.2616 light years.
Calculations and distances
The calculation of a light year is directly related to the speed of light. For calculations in physics, it is usually taken to be 300,000,000 m/s. The exact value of the speed of light is 299,792,458 m/s. That is, 299,792,458 meters is just one light second!
The distance to the moon is approximately 384,400,000 meters, which means that the light beam will reach the surface of the moon in approximately 1.28 seconds.
The distance from the Sun to the Earth is 149,600,000,000. Therefore, a sunbeam hits the Earth in a little less than 7 minutes.
So, there are 31,557,600 seconds in a year. Multiplying this number by a distance equal to one light second, we get that one light year is equal to 9,460,730,472,580,800 meters.
1 million light years, respectively, will be equal to 9,460,730,472,580,800,000,000 meters.
According to approximate calculations of astronomers, the diameter of our galaxy is about 100,000 light years. That is, within our Galaxy there cannot be distances measured in millions of light years. Such numbers are applicable for measuring distances between galaxies.
The Andromeda galaxy closest to Earth is 2.5 million light-years away.
To date, the largest cosmic distance from Earth that can be measured is the distance to the edge of the observable universe. It is about 45 billion light years.
Tip 2: How long is a light year in the cosmic dimension
The term "light year" is found in many scientific articles, popular TV shows, textbooks, and even in the news from the world of science. However, some people believe that a light year is a certain unit of time, although in fact, distance can also be measured in years.
How many kilometers in a year
In order to understand the meaning of the concept of "light year", you first need to remember the school physics course, especially the section that concerns the speed of light. So, the speed of light in vacuum, where it is not affected by various factors, such as gravitational and magnetic fields, suspended particles, refraction of a transparent medium, and so on, is 299,792.5 kilometers per second. It must be understood that in this case, light means those perceived by human vision.
Less well-known distance units are the light-month, week, day, hour, minute, and second.
A sufficiently long light was considered an infinite quantity, and the first person to calculate the approximate speed of light rays in a vacuum was the astronomer Olaf Roemer in the middle of the 17th century. Of course, his data were very approximate, but the very fact of determining the final value of the speed is important. In 1970, the speed of light was determined to within one meter per second. More accurate results have not been achieved so far, as there were problems with the error of the meter standard. Light year and other distances
Since the distances in are huge, measuring them in customary units would be irrational and inconvenient. Based on these considerations, a special light year was introduced, that is, the distance that light travels in the so-called Julian year (equal to 365.25 days). Considering that each day contains 86,400 seconds, it can be calculated that in a year a ray of light covers a distance of several more than 9.4 kilometers. This value seems huge, however, for example, the distance to the nearest star to the Earth, Proxima Centauri, is 4.2 years, and the diameter of the Milky Way galaxy exceeds 100,000 light years, that is, those visual observations that can be made now display a picture that existed about hundreds of thousands of years ago.
A beam of light covers the distance from the Earth to the Moon in about a second, but sunlight reaches our planet for more than eight minutes.
In professional astrophysics, the concept of a light year is rarely used. Scientists mainly operate with units such as the parsec and the astronomical unit. A parsec is the distance to an imaginary point from which the radius of the Earth's orbit is seen at an angle of one arc second (1/3600 of a degree). The average radius of the orbit, that is, the distance from the Earth to the Sun, is called the astronomical unit. A parsec is about 3 light years or 30.8 trillion kilometers. An astronomical unit is approximately equal to 149.6 million kilometers.
Tip 3: Is there a distance unit greater than a light year?
Meters, kilometers, miles and other units of measurement have been successfully used and continue to be used on Earth. But space exploration raised the question of introducing new measures of length, because even within the solar system you can get confused in zeros, measuring the distance in kilometers.
To measure the distance within the solar system, an astronomical unit was created - a measure of distance, which is equal to the average distance between the Sun and the Earth. However, even for the solar system, this unit does not seem quite suitable, which can be shown by a good example. If we imagine that the center of a small table corresponds to the Sun, and the astronomical unit is taken as 1 cm, then to designate the Oort cloud - the "outer boundary" of the solar system - you will have to move away from the table by 0.5 km.
If the astronomical unit was not large enough even for the solar system, all the more needed other units to measure the distances between stars and galaxies.
Light year
The unit of measurement of distance on the scale of the universe had to be based on some absolute value. This is the speed of light. Its most accurate measurement was made in 1975 - the speed of light is 299,792,458 m/s or 1,079,252,848.8 km/h.
The unit of measurement was taken as the distance that light, moving at such a speed, travels during an earthly non-leap year - 365 Earth days. This unit was called the light year.
At present, light years are more often indicated in non-fiction books and science fiction novels than in scientific works. Astronomers often use a larger unit, the parsec.
Parsec and its derivatives
The name "parsec" means "parallax of an arc second". An arc second is a unit of measurement of an angle: a circle is divided into 360 degrees, a degree is divided into 60 minutes, a minute is divided into 60 seconds. Parallax is the change in the observed position of an object depending on the position of the observer. According to the annual parallax of the stars, the distance to them is calculated. If we imagine a right-angled triangle, one of the legs in which is the semi-axis of the earth's orbit, and the hypotenuse is the distance between the Sun and another star, then the size of the angle in it is the annual parallax of this star.
At a certain distance, the annual parallax will be equal to 1 arc second, and this distance was taken as a unit of measurement called the parsec. The international designation of this unit is pc, the Russian one is pc.
A parsec is equal to 30.8568 trillion km or 3.2616 light years. However, for cosmic scales, this was not enough. Astronomers use derived units: equal to 1000 pc, - 1 million pc, and - 1 billion pc.
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 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 the Sun, 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.
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 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 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 while 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 are either highly fictional (like the Alcubierre drive) or exist only 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 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 quite successfully. 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 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.
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 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
The fastest way to space travel is by using the gravity assist. This method involves the spacecraft using the relative motion (i.e. orbit) and the planet's gravity 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.
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 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 of Space Systems at the Dresden University of Technology developed their 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 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-powered 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 significant 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.
