Nearest Earth-Like Planet “Only 20 Years Away”

Stephen Hawking, Mark Zuckerberg, and Yuri Milner must be overjoyed with the latest exciting discovery of an Earth-like planet in the Alpha Centauri solar system. Orbiting Proxima Centauri, one of three suns in Alpha Centauri, the newly discovered “Proxima b” is being hailed as the nearest Earth-like planet ever found.

Luckily for Hawking and his fellow Breakthrough Starshot co-founders, their laser-powered “nanocraft” now has a great place to land when it arrives in Alpha Centauri. Although it’s still on the drawing board, the high-tech spacecraft is expected to travel at 20 percent of the speed of light and could potentially reach Proxima b within 20 years of take-off.

Artistic illustration of Proxima b, the nearest Earth-like planet discovered in Alpha Centauri. Credit: NASA
Artistic illustration of Proxima b, the nearest Earth-like planet discovered in Alpha Centauri. Credit: NASA

Discovery of the Nearest Earth-like Planet

Announced last week (August 24) by European Southern Observatory (ESO) and subsequently in Nature, Proxima b was discovered by the Pale Red Dot team.

London’s Queen Mary University Astronomer Guillem Anglada-Escudé is the leader of the team that made the discovery. He explained, “The first hints of a possible planet were spotted back in 2013, but the detection was not convincing. Since then we have worked hard to get further observations off the ground with help from ESO and others. The recent Pale Red Dot campaign has been about two years in the planning.”

Astronomers from the Pale Red Dot campaign publicly monitored Proxima b between mid-January and April 2016 supported by the HARPS spectrograph on the ESO 3.6-metre telescope at La Silla in Chile.

Combining their data with ESO’s and other observations made elsewhere, the Pale Red Dot team detected an exciting signal. With a regularly alternating pattern every 11.2 days, Proxima Centauri approaches Earth at around 5 kilometers per hour (about 3.1 mph), the normal pace of human walking. Then it switches and recedes at the same speed.

By carefully analyzing the resulting tiny Doppler shifts, the team extrapolated the presence of an Earth-like planet orbiting Proxima Centauri from a distance of about 7 million kilometers (about 4,349,598 miles). The mass of the planet is approximately 1.3 times that of Earth.

Earth-like planet Proxima b is roughly 1.3 times the mass of Earth. Credit: NASA

Orbiting in the “Habitable Zone”

Proxima Centauri is a red dwarf star only four light-years away. Besides our sun, it’s the closest star to Earth, but it’s situated too near to the pair of stars known as Alpha Centauri AB to be seen without aid.

Although Proxima b orbits at only 5 percent of our Sun-to-Earth ratio, Proxima Centauri is much fainter and less hot than our sun. Daylight on the Proxima b is likely to be more like an orange-red sunset on Earth.

Research on Proxima b’s location indicates that it’s in the “habitable zone,” meaning that liquid water may be present. However, with a “year” lasting only 11.2 days, seasons are unlikely. And, like our moon, only one hemisphere faces Proxima Centauri, meaning one side of the planet is perpetually dark, and the sunny side may be receiving uninhabitable levels of radiation.

The Search for Life Comes Next

Undaunted by the challenging range of unknowns, Guillem Anglada-Escudé and his team see in Proxima b a prime target in the exciting hunt for extraterrestrial life on an Earth-like planet.

“Many exoplanets have been found and many more will be found,” says Anglada-Escudé, “but searching for the closest potential Earth-analogue and succeeding has been the experience of a lifetime for all of us.”

Rising to the challenge, Guillem Anglada-Escudé states, “The search for life on Proxima b comes next.”

Planning a Quick Trip to Alpha Centauri

Coincidentally planning a quick trip to Alpha Centauri, the Breakthrough Starshot team of esteemed astronomers, physicists, and billionaires are probably thrilled by Proxima b’s discovery.

Launched this past Spring on April 12, the Breakthrough Starshot initiative is the brainchild of Internet investor and science philanthropist Yuri Milner and world-renowned physicist Stephen Hawking.

Joining the board, Facebook founder Mark Zuckerberg has also taken up the incredible challenge to develop a 100-million-mile-per-hour mission to Alpha Centauri within the coming generation.

Breakthrough Starshot team
Breakthrough Starshot team. Credit:

With a budget of $100 million for research and engineering, the team will be led by Pete Worden, former director of NASA AMES Research Center. A world-class committee of space explorers, scientists, and engineers will serve as advisors.

Included among Worden’s stellar cast are such luminaries as Avi Loeb, Chairman, Breakthrough Starshot Advisory Committee and Frank B. Baird, Jr. Professor of Science at Harvard University; Freeman Dyson, Emeritus Professor, Princeton Institute for Advanced Study; Mae Jemison, NASA Astronaut, and Principal 100 Year Starship Foundation; and Ann Druyan of Cosmos Studios and wife of the late Carl Sagan.

Launched on the 55th anniversary of Yuri Gagarin’s premier voyage into space, Breakthrough Starshot plans to take the next great leap into our neighboring solar system. Aiming to demonstrate proof of concept for “light-propelled nanocrafts,” the team believes their design will achieve a velocity of 20 percent of the speed of light.

Expecting to reach Alpha Centauri in just over 20 years at this speed, the nanocraft will also capture images and collect data of planets along the way as it travels a distance of 1.3 parsecs or 4 light-years. The lucky discovery of Earth-like planet Proxima b in just the right neighborhood couldn’t have come at a better time.

Laser-propelled Nanocraft. Credit: Breakthrough Starshot Initiative
Laser-propelled Nanocraft. Credit:

Light-Propelled Nanocrafts

The Nanocrafts, as explained by the Breakthrough Starshot team, are “gram-scale robotic spacecrafts comprising two main parts:”

  • StarChip: Moore’s law has allowed a dramatic decrease in the size of microelectronic components. This creates the possibility of a gram-scale wafer, carrying cameras, photon thrusters, power supply, navigation and communication equipment, and constituting a fully functional space probe.
  • Lightsail: Advances in nanotechnology are producing increasingly thin and light-weight metamaterials, promising to enable the fabrication of meter-scale sails no more than a few hundred atoms thick and at gram-scale mass.

The Light Beamer needed to propel the nanocrafts is the other half of the visionary strategy:

  • Phased Arrays of Lasers: The rising power and falling cost of lasers, consistent with Moore’s law, lead to significant advances in light beaming technology. Meanwhile, phased arrays of lasers (the ‘light beamer’) could potentially be scaled up to the 100-gigawatt level.

Breakthrough Starshot “aims to bring economies of scale to the astronomical scale.” The team states, “The StarChip can be mass-produced at the cost of an iPhone and be sent on missions in large numbers to provide redundancy and coverage.”

“The light beamer is modular and scalable,” as well, reports Starshot. “Once it is assembled and the technology matures, the cost of each launch is expected to fall to a few hundred thousand dollars.”

That Sounds Easy, Doesn’t It? Maybe, But Then Again…

After a few years of research and engineering, the list of challenging tasks to develop an actual mission to Alpha Centauri sounds pretty incredible. Requiring a budget “comparable to the largest current scientific experiments,” Breakthrough Starshot aims to achieve the following goals:

  • Building a ground-based kilometer-scale light beamer at high altitude in dry conditions
  • Generating and storing a few gigawatt hours of energy per launch
  • Launching a ‘mothership’ carrying thousands of nanocrafts to a high-altitude orbit
  • Taking advantage of adaptive optics technology in real-time to compensate for atmospheric effects
  • Focusing the light beam on the lightsail to accelerate individual nanocrafts to the target speed within minutes
  • Accounting for interstellar dust collisions en route to the target
  • Capturing images of a planet, and other scientific data, and transmitting them back to Earth using a compact on-board laser communications system
  • Using the same light beamer that launched the nanocrafts to receive data from them over 4 years later.

One more tiny little detail… Breakthrough Starshot mentions in the fine print that “the proposed light propulsion system is on a scale significantly exceeding any currently operational analog.”

However, Elon Musk’s SpaceX is currently landing spaceships on tiny little barges in the ocean…:


(That took your breath away, admit it!)

…so anyway, after this, I can easily see Stephen Hawking sailing nanocrafts on laser beams to an Earth-like planet four light-years away. I just hope I’m alive to watch the live feed of the landing on Proxima b.

I was only four regular-years old, but I was watching the TV when John Glenn went up in space for the first time. I was also at Florida’s Kennedy Space Center to watch him go up for his famous space shuttle flight in 1998.

Maybe by the time the Breakthrough Nanocraft fleet sails to Proxima b, we’ll have super-cool VR viewers for really enjoying the show…!



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