Newly discovered planet holds potential to sustain humans
A new planet has been discovered that astronomers believe to have Earth-like conditions. Located just over four light-years away, Proxima b is thought be capable of holding liquid water, and with water, life.
Though much is still unknown about the planet, astronomers assert that Proxima b exists within what is called the “habitable zone,” or right distance from its host star to cause the planetary temperature to support liquid water.
Although Proxima b’s distance from its host star, Proxima Centauri, is small with an orbital period of 11.2 days and an orbit of only seven million kilometers—approximately 5 percent of the Earth’s average distance from the Sun—the planet is still considered to be in the habitable zone.
Proxima Centauri is a red dwarf star, with red dwarf stars being considerably dimmer than yellow dwarf stars, like the Sun. As a consequence, these stars give off less heat, potentially allowing Proxima b to sustain life on its surface.
However, while Proxima b may exist in a habitable zone, its position orbiting a red dwarf star reveals a whole new host of challenges of which habitants of Earth are not accustomed. The tight orbit of Proxima b to its star would most likely lock in a bound rotation, forcing one side of the planet to always be facing the Proxima Centauri in perpetual daytime, and the other side in endless nighttime. Contrasting sharply with the day-and-night cycle of Earth, astronomers believe that the bound rotation of Proxima b would make the evolution of life difficult.
Red dwarf stars are also entirely convective, and their matter is in constant motion. Combined with sudden releases of magnetic energy from the strong magnetic field that most red dwarf stars have, Proxima b is most likely doused with high energy particles and x-rays on a regular basis, making it even more difficult for sustained life to exist there.
Besides these facts, astronomers have theorized that the planet is rocky from studies of planets orbiting similar stars, making the chance of it being life-sustaining even slimmer. In an attempt to solve this mystery, astronomers are trying to determine whether Proxima b can pass across the face of its star in a process called transit. Transit would help to reveal the planet’s size, density and topography, though the chance of catching this process occurring is small.
Even with those doubts, many are looking to Proxima b as a new territory to examine. While there is an estimated 40 billion habitable, Earth-sized planets in the Milky Way galaxy, Proxima b is the closest one in reach, making it the most realistic option for those who wish to explore it.
Famed cosmologist Stephen Hawking and Russian billionaire Yuri Milner are the first pair to try and explore Proxima b with their nanocraft Breakthrough Starshot. While the nanocraft was originally slated to fly by Proxima Centauri, Hawking and Milner are making adjustments to the flight plan in order to make a flyby of Proxima b.
While Proxima Centauri is the closest star to us outside of our solar system, it does not mean the trip there will be short; the nanocraft would be expected to reach Proxima Centauri and Proxima b after a 20-year flight. This estimate is also unique to Hawking and Milner’s nanocraft, with its one gram weight and its projected ability to travel 20 percent the speed of light.
Astronomer Guillem Anglada-Escude and his colleagues first discovered Proxima b by studying the “wobbles” of Proxima Centauri as Proxima b orbited around it. When a planet passes a star in an orbit, both the planet and the star give off a gravitational pull on each other, making the star “wobble.”
This wobble can be detected on Earth through light emitted by the star, with the star turning slightly blue or red depending on which way it is moving. By timing the wobble, astronomers can discern the distance of a given planet to the star it orbits, revealing its location. Astronomers can also find out how large the mass of a given planet is via this method, with Proxima b appearing to be 1.3 times larger than Earth.
Proxima b has excited the astronomy community for now, but only time, effort and more research can uncover whether the planet is truly a suitable substitute for Earth.