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  • About 4.3 light-years from Earth lies our closest stellar neighborhood.

  • The Alpha Centauri system consists of three known stars.

  • Alpha Centauri A and Alpha Centauri B are a binary pair, which means they orbit a common center of mass.

  • The third star, Proxima Centauri, is the closest to Earth at about 4.22 light-years away.

  • In 2016, astronomers detected an Earth-sized planet orbiting Proxima Centauri within the

  • star's habitable zone - the right distance to potentially support liquid water on its surface.

  • Which is why eyes are on Alpha Centauri as our first destination once we master interstellar travel.

  • So is this deep space journey possible in our lifetime?

  • And if so, how will we get there?

  • Outer space is bigger than we can comprehend

  • and sending a spacecraft into its depths takes a lot of time.

  • NASA's Voyager 1 is Earth's farthest spacecraft to date.

  • It was launched in 1977, and in 2012, it was the first craft to enter interstellar space.

  • If Voyager 1 was pointed in the direction of Alpha Centauri, it would still take tens of thousands of years to reach the system.

  • And that's because its propulsion system is not ideal for deep space travel.

  • So clearly we need a faster way to get to our stellar neighbors.

  • Some scientists believe that our best attempt at interstellar travel are lightsails.

  • These sails would be made of ultra-thin sheets that will be propelled using light instead of wind.

  • One of the major initiatives researching their potential is Breakthrough Starshot.

  • The program, initially backed by late cosmologist Stephen Hawking, aims to create a nanocraft

  • comprised of a lightsail and a gram-scale wafer that hosts a number of instruments called a StarChip.

  • The nanocraft has a mirror-like sail design and is measured at 10 square meters with a mass of less than 1 gram.

  • By comparison a penny weighs 2.5 grams,

  • so these spacecraft will be ultralight.

  • The lightsail will purportedly be accelerated by laser radiation pressure from Earth at about 20 percent the speed of light.

  • The planned laser array, called a Light Beamer, will fire beams as powerful as 100 gigawatts of specific wavelengths of near-infrared light.

  • The nanocraft sail would need to reflect a huge majority of the laser light to avoid instantly burning up on contact.

  • The idea is to launch thousands of nanocraft at once to increase the chances that at least

  • a few will conquer the elements and reach Alpha Centauri.

  • If they do make it, it's estimated, the journey will only take around 20 years.

  • Though some critics are skeptical about the ability to execute Breakthrough Starshot,

  • some of the world's greatest minds are actively working to make it a reality.

  • The project is pushing the boundaries of science, challenging humans to create an entirely new

  • material that meets all the extreme needs of the lightsails

  • and to design the largest laser ever constructed.

  • But, if engineers and scientists are able perfect these pint-sized spacecraft and we

  • achieve interstellar travel, humanity will be rewarded with an entirely new understanding of the alien worlds beyond our own.

  • If you're looking to learn more about space exploration and astronomical phenomena be sure to watch this episode of Space Crafts.

  • And don't forget to subscribe to Seeker for all things science.

  • Thanks for watching!

About 4.3 light-years from Earth lies our closest stellar neighborhood.


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B2 中上級

どうやってケンタウリ星に行くの? (How Will We Get to Alpha Centauri?)

  • 55 7
    Jerry Liu に公開 2021 年 01 月 14 日