A Possibly Habitable Earth-Like Planet Discovered Just 4 Light Years Away


A team of scientists recently announced the discovery of a new planet not far from our Solar System. A discovery of this caliber is fairly typical in the astronomy field, so why are scientists, popular media outlets, and regular people like me and you getting so excited about it?

Because this planet could be another Earth!

It sounds crazy, we know. We’re more used to hearing about planets being downgraded and stars being named, or NASA exploring planets and moons orbiting our own Sun.

But, this new planet, currently dubbed Proxima b, gives us a lot to be excited about.

How is it another Earth?

Beyond our Solar System, we have a few neighbors nearby. The Alpha Centauri star system is cosmically close in distance to us, and one of the stars within that group is called Proxima Centauri. The existence of this red dwarf star has been known for a long time.

Over the course of this year, a team of scientists have been using a unique method to study the space around Proxima Centauri, and they’ve announced their findings: a planet that orbits Proxima Centauri.

Because of this planet’s location and relationship to its parent star, it’s situated in the so-called “Goldilocks zone”, meaning the temperatures might not be too hot or too cold, but just the right temperatures for water to exist.

And if water exists, the possibility of life exists.

While many acknowledge that this isn’t the only planet we’re aware of with the possibility of life, this situation is so extraordinary because it’s located only 4.2 light years away from Earth, or the equivalent of 25 trillion miles. (We know from the guide to the universe that this is actually very near, in cosmic terms.)

At only 4.2 light years away, there’s a real possibility that we could reach this new ‘Earth’, potentially even in six or seven decades. Imagine the possibilities.

One of the scientists responsible for this discovery, R. Paul Butler from the Carnegie Institute of Science, compared this discovery to a huge arrow on Proxima Centauri saying: “I’m the nearest star, and I have a potentially habitable planet!”

Indeed, the excitement about this planet discovery isn’t so much that it’s a planet; instead, the science community is excited because of its proximity to us.

This discovery “raises the public awareness [that] there’s a new world just next door,” said Dr. Belikov, an astronomer with NASA Ames Research Center in Mountain View, California. He encouraged this “paradigm shift” in how the public should think about science advances.

The starting point of Proxima b

This discovery is raising a lot of attention, and inspiring scientists and laypeople alike to ask a lot of questions about real potential in reaching Proxima b.

Here’s what we do know about the planet:

Proxima b

Image via Newscientist.com

Proxima b hasn’t been seen directly, similar to recently discovered Planet 9. It was instead detected using technology called the radial velocity method. This allows telescopes to pick up periodic oscillations of spectral lines of the parent star, and these shifts suggest an orbiting object.

The team of scientists responsible for the discover, part of the European Southern Observatory which is a collective of 16 nations, started the Pale Red Dot Project in January 2016. This wasn’t the first time astronomers had hints of a possible planet here, but the Pale Red Dot Project confirmed it.

Compared to our Earth, Proxima b is at least 1.3 times the mass, though it could be much larger. One year on Proxima b, the time to fully orbit around its parent star once, is a mere 11.2 days.

Proxima B is also significantly closer to Proxima Centauri, its parent star, at only 5 million miles away. For comparison, Earth is 93 million miles away from the Sun, and the closest planet to the Sun, Mercury, is still 36 million miles away. Because of its proximity to Proxima Centauri, the newly discovered planet likely experiences tidal locking with its parent star – so that one side is bright all the time, with the other side facing away from the star perpetually, much like Earth and our moon.

Simulated comparison of a sunset on Earth and Proxima b

Simulated comparison of a sunset on Earth and Proxima b. Credit: PHL @ UPR Arecibo.

While Earth and Proxima b may have similarities, our Sun and Proxima Centauri are vastly different. Proxima Centauri is tiny, part of the red dwarfs star class. It has only 12 percent the mass of our Sun, and 1/600th the luminosity, so the naked eye can’t see it from Earth. Because of this, Proxima b receives less warmth than we do, despite its proximity.

It could still have enough warmth that surface water or an atmosphere may exist, though some scientists say that it’s complete speculation right now.

Missing pieces of Proxima b

Because we haven’t seen Proxima b directly yet, we have no pictures of it. This may change as the next generation of telescope are built in another decade.

As for its surface conditions, we simply don’t know yet. Is it Earth-like, or more similar to the heat of Venus, or the cold desert of Mars?

The other ambiguous part is whether there are more planets like it. Scientists say only time will tell.

Continuing Exploration

While science is still searching for more answers regarding Proxima b, it hasn’t stopped other industries from latching on with potential ideas.

Physicist Stephen Hawking and Russian entrepreneur Yuri Milner have developed an initiative called Breakthrough Starshot. The purpose is to launch tiny spacecraft within the next 30 years – and these spacecraft would be the size of a smartphone! They would explore the Alpha Centauri star system, of which Proxima Centauri is part. The Initiative had already announced this goal before the discovery of Proxima b, but they’ve confirmed that Proxima Centauri and its planet are goals for exploration, too.

To go ever farther is what exploring space is about: some scientists and entrepreneurs even believe that in several decades, interstellar travel will be a real thing.

References: Nature, New York Times, Popular Mechanics, Wikipedia

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