It’s our closest star system, and it may offer the best chance of finding extraterrestrial life – but reaching Alpha Centauri with current technology would take thousands of years.
The good news is that scientists may have only found one way to get there within a human lifetime.
It’s a laser-powered sail that they claim could one day allow us to travel 24 trillion miles and reach our closest stellar neighbor in 20 years.
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Concept: Scientists develop a laser-powered sail (shown in an artist’s impression) that they claim could enable us to travel 24 trillion miles to Alpha Centauri in 20 years
This graphic shows how the laser powered sail for Alpha Centauri. would start from Earth
WHAT IS ALPHA CENTAURI AND HOW CAN WE GET INTO IT?
The Alpha Centauri star system is 24 trillion miles (4.37 light years) away.
With today’s fastest spaceship, it would take thousands of years to get there.
Breakthrough Starshot aims to find out whether a nano vehicle in the gram range can fly over a thousand times faster on a sail pushed by a beam of light.
Astronomers estimate that in the “habitable zones” of Alpha Centauri’s three-star system, there is a reasonable chance that an Earth-like planet exists.
The novel propulsion system for spacecraft was developed by scientists from the Australian National University (ANU) as part of an international initiative to explore the worlds around Alpha Centauri.
The Breakthrough Starshot project requires the development of an ultra-light spaceship that will act as a sail of light to travel at unprecedented speed to the triple star system 4.37 light-years away.
Although this is a great distance on Earth, it is three times closer than the closest Sun-like star.
The concept calls for probes to be launched into space by the laser propulsion system.
The light to propel the sail would come from the surface of the earth – with millions of lasers joining together to illuminate the sail and propel it on its interstellar journey.
“To overcome the vast distances between Alpha Centauri and our own solar system, we need to think outside the box and pave a new path for interstellar space travel,” said Dr. Chathura Bandutunga, lead author of the study.
“Once the sail is underway, it will fly through the vacuum of space for 20 years before it reaches its destination. During its flyby of Alpha Centauri, it will record images and scientific measurements that it will send back to Earth. ‘
Alpha Centauri is 4.37 light years away and is home to three stars: Centauri A, Centauri B, and Proxima Centauri. An artistic impression of the star system closest to us is shown
Shown is a not to scale representation of Proxima B’s distance from Earth compared to Voyager 1, the most man-made object, launched in 1977
One potential stumbling block, however, is the sheer size of the lasers required to send the probes on their way and get them to act as a unit.
“The Breakthrough Starshot program estimates the total optical power required to be approximately 100 GW – about 100 times the capacity of what is currently the largest battery in the world,” said Dr. Robert Ward from the ANU Research School of Physics.
“To achieve this, we estimate the number of lasers needed to be around 100 million.”
Proxima b: The closest exoplanet to Earth
Proxima b is the closest exoplanet to Earth and the closest planet to the star Proxima Centauri.
It orbits within the star’s habitable zone – but since Proxima Centauri is a red dwarf and much smaller than the Sun, this zone is very close to the star.
Proxima b orbits its star every 11.2 Earth days and has a mass about 1.2 times that of Earth.
The rocky world is exposed to solar winds that are 2,000 times higher than on earth from the sun.
While in a zone where liquid water could form, these stellar winds make it unlikely that life could evolve.
The planet was discovered in August 2016 and is likely locked by tides.
For these reasons, although it is in the habitable zone, the actual habitability has not been established.
Studies have suggested the planet might have surface oceans and a thin atmosphere, but that hasn’t been confirmed.
Astronomers won’t know if it has water or an atmosphere until it can pass in front of its star – which has not yet happened.
If there is water and an atmosphere, life could have evolved on the planet despite the extensive radiation.
Scientists hope that the James Webb Space Telescope, due to go online this November, could discover the atmosphere of Proxima Centauri b.
There is also a theoretical mission to send a probe to the planet in 2069 to look for biosignatures.
To orchestrate the show, the ANU design requires a beacon satellite – a guide laser placed in earth orbit that acts as a conductor to bring all of the lasers together.
Dr. Bandutunga said that just like the later light sail, research is at the beginning of a long journey.
“Although we believe in our design, the proof is in the pudding,” he said.
“The next step is to test some of the basic building blocks in a controlled laboratory environment. This includes the concepts of combining small arrays into larger arrays and the atmospheric correction algorithms.
“The ANU’s work was to see if this idea would work at all. The aim was to find out-of-the-box solutions, to simulate them and to determine whether they are physically possible. ”
In 2017, NASA announced that it had started planning a mission to Alpha Centauri in hopes of launching on the 100th anniversary of the Apollo 11 mission in 2069.
Currently, only two man-made spaceships have left our solar system – Voyager 1, which launched 40 years ago and is currently flying at around 38,000 mph, and its twin ship Voyager 2.
Voyager 2 was launched 16 days before Voyager 1 in 1977, but the latter was the first to reach interstellar space in 2012 due to its faster trajectory. His twin left our solar system six years later.
Alpha Centauri hosts three stars: Centauri A, Centauri B and Proxima Centauri.
Last December, astronomers announced they were “carefully investigating” a mysterious radio signal from Proxima Centauri, a red dwarf star in the Alpha Centauri system.
Proxima Centauri is 4.2 light years from Earth and has two confirmed planets, a Jupiter-like gas giant and a rocky world called Proxima b in the habitable zone.
The signal was discovered by the Parkes Radio Telescope in Australia in April or May 2020 and, unlike previous radio bursts, has not been ascribed to an Earth-based or near-Earth man-made source.
It’s likely that this signal has some natural explanation, but that hasn’t stopped the alien astronomers from listening more closely than they normally would.
Researchers at the Breakthrough Listen Project – a £ 70 million initiative to find extraterrestrial life through radio telescopes – said it was one of the most exciting radio signals since the ‘WOW!’ Signal from 1977 that led many to believe that it came from a distant alien civilization.
The ANU study was published in the Journal of the Optical Society of America B.
The project involves using thousands of tiny spaceships to travel to our nearest star system and send back images.
If successful, scientists could determine whether Alpha Centauri, a star system about 25 trillion miles away, contains an Earth-like planet.
The catch: The Breakthrough Starshot project could take years to develop and there are no guarantees that it will work.
The small light vehicles will carry equipment such as cameras and communication devices.
This includes a ground-based light emitter that propels ultra-light nano-vehicles – miniature space probes attached to light sails – to speeds of up to 100 million miles per hour.
Such a system would allow a flyby mission to reach Alpha Centauri in just over 20 years from launch.
Breakthrough Starshot aims to demonstrate the proof of concept for ultrafast light-powered nano vehicles and lay the foundation for an initial launch of Alpha Centauri within the next generation. Along the way, the project could bring important additional benefits to astronomy, including exploration of the solar system and the discovery of earth-crossing asteroids.
Scientists hope that the vehicles known as nanocrafts will eventually fly at 20 percent the speed of light.
“That thing would look like the chip on your cell phone with this very thin, wafer-thin sail of light,” said Pete Worden of NASA
“It would be about 10, 12 feet wide.”
He envisions putting a larger conventional spaceship with thousands of nano-vehicles into orbit and then launching the nano-vehicle.
Should they reach the star system and photograph them successfully, it would take about four years to send them back.