Our ambitions for space exploration have boldly sent humans to the Moon, probes to Mars, and spacecraft to the ends of the Earth. Solar SystemBut can humans and spacecraft ever reach Alpha Centauri, the closest star system to Earth?
Alpha Centauri is about 4.4 Light years (about 25 trillion miles, or 40 trillion kilometers, from Earth) and is home to three separate stars. The closest star, Proxima Centauri, is one that scientists believe may host an exoplanet. The conditions necessary for life.
But reaching this star system will not be easy. National Aeronautics and Space Administration (NASA) Like NASA’s retired 122-foot (38-meter) long space shuttle. discovery,it is Nearly 150,000 years Reach Alpha Centauri.
If humans Speed of LightThat would take four years to reach Alpha Centauri. But the laws of physics dictate that only massless particles called photons can reach the speed limits of our universe. So while humans will probably never reach Alpha Centauri, a spacecraft designed to travel at just under the speed of light could potentially reach these stars within a human lifetime. Scientists would need something much smaller than Discovery if they even had any hope of accelerating a spacecraft up to its top speed.
Marshall EubanksAs CEO of the startup Space Initiatives and a researcher at NASA’s Innovative Advanced Concepts, he’s investigating remote visits to Proxima Centauri using a swarm of picometer-sized spacecraft (a picometer is one trillionth of a meter).
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“We are in the midst of a true revolution in spaceflight and exploration with extremely small systems,” Eubanks told LiveScience in an email. “While individual small spacecraft do not have the capabilities of larger spacecraft like Voyager, they can be developed much faster and are relatively inexpensive.”
Smaller spacecraft also require less power to propel themselves, which could be a key advantage in increasing speed.
Eubanks is not the only one doing this kind of research. The Breakthrough Initiative Starshot Project In 2016, a nanometer-sized spacecraft was combined with a light sail. 2017NASA has begun funding its own projects to launch missions. Alpha Centauri by 2069100 years after Apollo 11.
Small spacecraft are easier to accelerate than larger spacecraft, but traditional fuel sources alone do not have enough power or mass to accelerate these craft to near the speed of light. Instead, Philip RubinDavid K. Schneider, a physics professor at the University of California, Santa Barbara, who brought the idea of interstellar travel to the Starshot team, told Live Science that these spacecraft will likely rely on light.
Solar Energy
To travel fast in space, small size and low mass are advantageous, and Rubin said one big advantage of light-powered propulsion is the lack of mass. In contrast, traditional rocket fuel creates thrust by burning heavy fuel and converting it into energy. With a solar sail, propelled by sunlight, or a photonic sail, propelled by laser light, you get all the power without having to worry about weight at all.
Rubin said to think of it like throwing a ball at a piece of paper. When the ball hits the paper, it exerts a force that causes the paper to bounce or be pushed away. The momentum carried by light is transferred It strikes the spacecraft, causing recoil and acceleration.
“The system is basically a giant flashlight, a giant laser array. [on Earth]”If the spacecraft is a sailing ship, the laser light is the wind in the sail,” Rubin said.
The technology to build and test such a craft — including communications equipment small enough to fit on board — is still being developed, but Rubin said there’s no physical reason to think such a craft couldn’t perform a flyby mission to Alpha Centauri.
The mission would function in much the same way as the Voyager 1 and 2 probes, potentially transmitting high-resolution images of the star system to Earth, some of which may include the first images of a potentially habitable planet at Proxima Centauri.
Rubin stressed that the journey to Alpha Centauri will be a long-term endeavor, but Eubanks said he is confident that significant progress will be made this century.
“I think we could launch small probes in the 2040s and reach the Alpha Centauri system in the 2060s,” Eubanks said. “Much larger probes should be possible by the end of the century, but barring unexpected advances in propulsion physics, I think manned missions will be a challenge for the next century.”
