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This is What Our Nearest Exoplanet May Look Like - A Giant Eye Staring at the Sun

The nearest exoplanet ever has been observed, but not yet seen. Is this what the 'Earth Next Door' looks like?

An eyeball planet

Donald Who? Centuries after this era's headlines are forgotten, 2016 will be remembered as the year we discovered our 'Planet B'. 

Because even if we find a billion more Earth-like exoplanets, none will ever be closer to home than Proxima Centauri b, spotted circling our nearest star (1) on August 24th of last year. At a mere 4.25 light-years away, it is close enough for us to contemplate visiting, and perhaps even living there.

One of the few things we know about Proxima b, besides that it is a rocky planet with a mass 1.3 times that of Earth, is that its orbit is in the so-called 'Goldilocks zone' of its sun: not too hot nor too cold for liquid water, making it a potential host for life – alien, human or both.

So what does this 'Earth Next Door' look like? We don't really know. Planet B has only been observed indirectly, via Doppler spectography. If we sent a spacecraft there tomorrow, it would take decades for it to get there and send home pictures. 

But we can speculate. And this is what Proxima B could very well look like: an 'Eyeball Earth'.

Eyeball Earth: it sounds weird and it is weird. Tidally locked with its sun, an Eyeball Earth consists of three extreme climatic zones – scorchingly hot on the permanent day side, icy cold on the permanent night side. In between, ringing the planet: a thin, potentially habitable strip.

This setup gives the planet the appearance of an eyeball. Permanently staring into the sun.

The concept of an Eyeball Earth was kicked off by the discovery in 2010 of Gliese 581g, in the Goldilocks zone of its parent star, a red dwarf. Scientists speculated this planet type, occurring around red dwarfs, would be the likeliest candidate for life to evolve on. 

Red dwarfs, a.k.a. M stars, make up around 75% of the stars in our galaxy. They are smaller and dimmer than our own sun, so their Goldilocks zone is much closer by than in our case (our sun is a yellow dwarf). Hence the tidal lock (2).

A year on Proxima b only lasts 11.2 Earth days. That's how long the planet takes to revolve around its sun - our nearest star Proxima Centauri, a red dwarf about one-seventh the diameter of our sun, and one-eighth the mass. The planet's distance from its sun is only 7.5 million km, or 1/20th of the Earth's orbit around the sun. So our Planet B could very well be an Eyeball Earth. 

But will we really have to get there to be sure? Some scientists hope that the James Webb Space Telescope, to be launched in 2018,  will be able to deliver some answers. Whether it is in fact tidally locked with its sun, for example. And, crucially, whether it has an atmosphere. If so, life is possible – in that 'ring of habitability', between the planet's hot and cold halves, their extremes mitigated by the atmosphere's redistribution of heat. Without an atmosphere, Proxima b might be a lifeless rock after all. 

Astronomers only started detecting exoplanets – i.e. planets outside our own solar system – in the 1990s. By now, they've identified as many as 3,000, plus another 2,500 possible ones. In 2013, it was estimated there could be about one billion 'Earths' in our galaxy. If the presence of Proxima b at our nearest star is an indication of their prevalence – i.e. at least one around each star – we could be looking at as many as 500 billion 'Earths' in our galaxy.

That's a lot of eyeballs. Next time you're under the stars at night, looking up at the Milky Way, just think of all those stares in your direction. Perhaps even literally. Who knows, in that habitable strip on Proxima b, somebody might be aiming a telescope at us, to check whether our rock has an atmosphere. 

Image by Beau.TheConsortium, found here on

Strange Maps #801

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(1) A top ten of closest stars:

1 Proxima Centauri (4.25 ly) – in the same star system as the next two.

2 Alpha Centauri A (4.36 ly) – the main star in Centaurus, a constellation in the southern sky.

2 Alpha Centauri B (4.36 ly) – slightly smaller and less luminous than both our sun and Centauri A.

4 Barnard's Star (5.96 ly) – the closest star in the Northern Hemisphere.

5 Luhman 16A (6.59 ly) – the primary in a binary brown-dwarf constellation, discovered only in 2013.

5 Luhman 16B (6.59 ly) – orbits its companion star at a distance of about 3 AU, with a period of about 25 years.

7 WISE 0855−0714 (7.20 ly) – located in the constellation Hydra, its discovery was announced in 2014 by the people that also brought you #5.

8 Wolf 359 (7.78 ly) – with a cool name like that, it's no wonder this star crops up in lots of sci fi, from Terry Pratchett to Star Trek.

9 Lalande 21185 (8.29 ly) – a red dwarf in the constellation Ursa Major.

10 Sirius A (8.58 ly) – main star of a binary system that is the brightest object in the night sky

10 Sirius B (8.58 ly) – a white dwarf much smaller than Sirius A, with which it is locked in a 50-year orbit.

(2) Like the Moon with the Earth, which is why we only ever see one side of our natural satellite. The Moon's other side gets as much sunlight as the Earth-facing side. It is only 'dark' in the sense that is was unknown for so long (the Soviets had it mapped by 1960).

Radical innovation: Unlocking the future of human invention

Ready to see the future? Nanotronics CEO Matthew Putman talks innovation and the solutions that are right under our noses.

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Your body’s full of stuff you no longer need. Here's a list.

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Quantum particles timed as they tunnel through a solid

A clever new study definitively measures how long it takes for quantum particles to pass through a barrier.

Image source: carlos castilla/Shutterstock
  • Quantum particles can tunnel through seemingly impassable barriers, popping up on the other side.
  • Quantum tunneling is not a new discovery, but there's a lot that's unknown about it.
  • By super-cooling rubidium particles, researchers use their spinning as a magnetic timer.

When it comes to weird behavior, there's nothing quite like the quantum world. On top of that world-class head scratcher entanglement, there's also quantum tunneling — the mysterious process in which particles somehow find their way through what should be impenetrable barriers.

Exactly why or even how quantum tunneling happens is unknown: Do particles just pop over to the other side instantaneously in the same way entangled particles interact? Or do they progressively tunnel through? Previous research has been conflicting.

That quantum tunneling occurs has not been a matter of debate since it was discovered in the 1920s. When IBM famously wrote their name on a nickel substrate using 35 xenon atoms, they used a scanning tunneling microscope to see what they were doing. And tunnel diodes are fast-switching semiconductors that derive their negative resistance from quantum tunneling.

Nonetheless, "Quantum tunneling is one of the most puzzling of quantum phenomena," says Aephraim Steinberg of the Quantum Information Science Program at Canadian Institute for Advanced Research in Toronto to Live Science. Speaking with Scientific American he explains, "It's as though the particle dug a tunnel under the hill and appeared on the other."

Steinberg is a co-author of a study just published in the journal Nature that presents a series of clever experiments that allowed researchers to measure the amount of time it takes tunneling particles to find their way through a barrier. "And it is fantastic that we're now able to actually study it in this way."

Frozen rubidium atoms

Image source: Viktoriia Debopre/Shutterstock/Big Think

One of the difficulties in ascertaining the time it takes for tunneling to occur is knowing precisely when it's begun and when it's finished. The authors of the new study solved this by devising a system based on particles' precession.

Subatomic particles all have magnetic qualities, and they spin, or "precess," like a top when they encounter an external magnetic field. With this in mind, the authors of the study decided to construct a barrier with a magnetic field, causing any particles passing through it to precess as they did so. They wouldn't precess before entering the field or after, so by observing and timing the duration of the particles' precession, the researchers could definitively identify the length of time it took them to tunnel through the barrier.

To construct their barrier, the scientists cooled about 8,000 rubidium atoms to a billionth of a degree above absolute zero. In this state, they form a Bose-Einstein condensate, AKA the fifth-known form of matter. When in this state, atoms slow down and can be clumped together rather than flying around independently at high speeds. (We've written before about a Bose-Einstein experiment in space.)

Using a laser, the researchers pusehd about 2,000 rubidium atoms together in a barrier about 1.3 micrometers thick, endowing it with a pseudo-magnetic field. Compared to a single rubidium atom, this is a very thick wall, comparable to a half a mile deep if you yourself were a foot thick.

With the wall prepared, a second laser nudged individual rubidium atoms toward it. Most of the atoms simply bounced off the barrier, but about 3% of them went right through as hoped. Precise measurement of their precession produced the result: It took them 0.61 milliseconds to get through.

Reactions to the study

Scientists not involved in the research find its results compelling.

"This is a beautiful experiment," according to Igor Litvinyuk of Griffith University in Australia. "Just to do it is a heroic effort." Drew Alton of Augustana University, in South Dakota tells Live Science, "The experiment is a breathtaking technical achievement."

What makes the researchers' results so exceptional is their unambiguity. Says Chad Orzel at Union College in New York, "Their experiment is ingeniously constructed to make it difficult to interpret as anything other than what they say." He calls the research, "one of the best examples you'll see of a thought experiment made real." Litvinyuk agrees: "I see no holes in this."

As for the researchers themselves, enhancements to their experimental apparatus are underway to help them learn more. "We're working on a new measurement where we make the barrier thicker," Steinberg said. In addition, there's also the interesting question of whether or not that 0.61-millisecond trip occurs at a steady rate: "It will be very interesting to see if the atoms' speed is constant or not."

Self-driving cars to race for $1.5 million at Indianapolis Motor Speedway ​

So far, 30 student teams have entered the Indy Autonomous Challenge, scheduled for October 2021.

Illustration of cockpit of a self-driving car

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  • The Indy Autonomous Challenge will task student teams with developing self-driving software for race cars.
  • The competition requires cars to complete 20 laps within 25 minutes, meaning cars would need to average about 110 mph.
  • The organizers say they hope to advance the field of driverless cars and "inspire the next generation of STEM talent."
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