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Two interesting divergent views on the exoplanet Proxima Centauri b August 27, 2016

Posted by WorldbyStorm in Uncategorized.

So, astronomers have discovered a planet orbiting the closest star to the Sun. Proxima Centauri b is thought to be a little larger than the Earth, to orbit one hell of a lot closer to its star than the Earth does to the Sun and yet due to the nature of that star to receive about two-thirds of the light and heat that we do from our Sun. All in all that means as Phil Plait says:

…it’s in Proxima’s habitable zone: It’s possible (more or less) that liquid water could exist on its surface.

And Phil Plait considers this to be a genuinely important moment.

…this is terribly, terribly exciting. We’ve only known for sure about the existence of exoplanets—worlds orbiting alien suns—since 1992. The first found were orbiting a dead star, a pulsar. The first planet orbiting a Sun-like star wasn’t found until 1995, and in the next two decades we built telescopes dedicated to looking for them, and as of today we know of over 3,000 such strange, new worlds.
Quite a few are Earth-size, and fewer possibly Earth-like. Still, we can make estimates that there are billions of Earth-size planets in the galaxy.
And now we know that it’s possible that the nearest one is, on a cosmic scale, right next door.

Whereas Charles Stross is a lot cooler on the issue, albeit he pivots the argument to consider actually sending a probe to this planet. In part because he notes the reality of distance in space. Right next door is nothing of the sort.

I don’t want to minimize the significance of the discovery; it’s certainly a good addition to the list of potentially habitable exoplanets here, but you will note that 4.25 light years isn’t an order-of-magnitude improvement over the previous winners for Earthlike proximity, such as Wolf 1061c (13.8 light years away) or Kapteyn B* (12.76 light years away). We’re talking about the difference between 40 arbitrarily-huge-units and 100 arbitrarily-huge-units. So how should we contextualize these arbitrarily-huge-units?
Currently, the most distant visited body in the solar system is Pluto, at 7.5 billion kilometers. The New Horizons probe flew past Pluto on July 14, 2015. It was launched on January 19th 2006 by a booster and upper stage combination that blasted it straight up to solar escape velocity, with a speed of 16.26 km/sec (58,536 km/h), making it the fastest human-made vehicle ever: it then executed a Jupiter gravity-assist flyby to slingshot it out past Pluto, where it arrived nine and a half years after departure.
This veritable speed racer of an interplanetary probe would thus require a mere 31,600 years to reach Proxima Centauri (if indeed it was pointed in the right direction, which it isn’t).

Space is vast. Unbelievably incredibly vast. The distances between stars that are close to one another in stellar terms is, on a human scale, so daunting as to defy our ability at this point to bridge that gap in any satisfactory timescale.

That’s not to say never, but as Stross notes, we’re not even close to having technologies that would allow us to send probes to Proxima Centauri b. Perhaps won’t have that ability for hundreds, possibly thousands of years.

Interesting discussion btl on Stross. And one slightly more optimistic contributor does make some good points in the following:

The importance of a possible Proxima Centauri Planet (PCP) are the following:
a. It is another “close” planet orbiting a red dwarf star. Currently, what we know about planets orbiting red dwarf stars is inferred from computer models. PCP is close enough that we can get very low-resolution measurements against which we can test our models. Testing and refining these models is very important
b. It is a close target against which we can test new technologies. We can already photographed whole planets. I don’t know how much this proximity would increase resolution. The same holds true for studying a potential atmosphere
c. There was talk of using the same method previously used to confirm Europa’s ocean being used to study planetary geology. Assuming it is a rock world, this planet is close enough and the star is small enough that we might begin using it to study geology? I wonder if present methods can infer the presence of plate tectonics?
d. Its existence is really cool and might confirm a cliche


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