There may be something orbiting Proxima

August 26th, 2016 at 8:51:57 AM permalink
Nareed
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Recently the discovery of a planet around Proxima Centauri was announced. I recall a similar announcement not too long ago. This time we're told it's at a distance from its star that would allow for the existence of liquid water on its surface, meaning it meets one requirement for being hospitable to life.

I hope there's really something there. But red dwarf stars are notoriously good at producing spurious signals. They flare too much. So I'll hold my enthusiasm until this discovery is confirmed through other sources. Provisionally this would-be planet has been dubbed "Proxima b."

The liquid water datum is interesting, but there is a vast difference between "it can have liquid water on the surface," and "there is liquid water on the surface." Never mind to "there is life there."

To give you some perspective, the Earth, the Moon, Venus, Mars, Phobos and Deimos all lie at a distance from the Sun which allows for the existence of liquid water on their surface. Of all these bodies, only one has actual liquid water on it surface. Mars had it in the past, and may have it sporadically now. But that's a far cry from Earth.

The good news is Proxima is the closest star to the Sun, along with its companions Alpha and Beta. the bad news is that it's a dim, flare-prone red dwarf star, relatively cool and very active. Meaning Proxima b, if it does exist, may be tidally locked, perpetually showing one face to its parent star.

Following up on the good news, it means we may be able, in the very near future, to obtain much more data about it than about any other exoplanet in the galaxy. And in the not so near future, it wouldn't be impossible to send probes there.

There are also reports of hints that a second planet might be orbiting Proxima as well.
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August 26th, 2016 at 9:10:36 AM permalink
Pacomartin
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Quote: Nareed
The good news is Proxima is the closest star to the Sun, along with its companions Alpha and Beta. the bad news is that it's a dim, flare-prone red dwarf star, relatively cool and very active. Meaning Proxima b, if it does exist, may be tidally locked, perpetually showing one face to its parent star.


The fact that it is the closest star makes me think that planets might be commonplace. But at escape velocity of 25,000 mph that is still 116,000 years to get there. I think we have achieved 4* escape velocity with a probe. Is there any way to achieve speeds of thousands of times escape velocity?
August 26th, 2016 at 9:48:20 AM permalink
rxwine
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Quote: Pacomartin
. Is there any way to achieve speeds of thousands of times escape velocity?


Apparently we could get objects the size of a quarter there in 20 years. I'm not sure if it's some sort of multi-stage vehicle or something else. Still on the drawing board.
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August 26th, 2016 at 10:17:58 AM permalink
Pacomartin
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Quote: rxwine
Apparently we could get objects the size of a quarter there in 20 years. I'm not sure if it's some sort of multi-stage vehicle or something else. Still on the drawing board.


Thank you. I had not heard about that initiative

https://breakthroughinitiatives.org/Initiative/3

This involves a ground-based light beamer pushing ultra-light nanocrafts – miniature space probes attached to lightsails – to speeds of up to 100 million miles an hour. Such a system would allow a flyby mission to reach Alpha Centauri in just over 20 years from launch, and beam home images of possible planets, as well as other scientific data such as analysis of magnetic fields.
August 26th, 2016 at 10:20:33 AM permalink
Nareed
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Quote: Pacomartin
The fact that it is the closest star makes me think that planets might be commonplace.


Planets are commonplace. The Kepler probe has shown that.

But, given our level of technology and given natural facts and laws, thus far the easiest planets to detect are larger ones closer to their primaries.

Quote:
But at escape velocity of 25,000 mph that is still 116,000 years to get there. I think we have achieved 4* escape velocity with a probe. Is there any way to achieve speeds of thousands of times escape velocity?


There are many ways. If we exclude exotic propulsion systems we've yet to develop at a fundamental level, like antimatter and nuclear fusion, there are still many ways. The easiest, but not cheapest, would be to propel a craft with nuclear bombs. But that means a large, heavy craft. We could try a fission reactor to heat propellant, but that also means a heavy craft with lots of shielding for the electronics; not to mention opposition to flying nuclear reactors in rockets.

This leaves us with ion drives and solar sails as best candidates. I favor the latter, as it requires very little fuel after launch and can, potentially, reach amazing speeds. We can also add propulsive power to it with effing BIG lasers. A solar sail probe could use the destination star's light to slow down and maneuver, too. it would be a bit unproductive to send a probe at 0.05c, and then have it traverse the Centauri system at that speed, bound for unknown places. We wouldn't get much of a look at Proxima b that way. But given the three stars there, that's a lot of photons with which to slow down, perhaps enough to have the probe stay in system for an indefinite period.

A solar sail needs to be shiny, as the idea is to bounce photons off it to get them to transfer momentum. So it would serve nicely as an antenna as well. If the reverse side were made of solar cells, it would serve as a power source. if not, then you could still use the shiny part to concentrate sunlight on something and turn that into electricity.

0.05c is 1/20th the speed of light. If we can achieve this, it would still take the probe 100 years or so to get there (4.5 light years times 20 plus acceleration times; deceleration would occur at the destination). So we wouldn't live to see it, but it's a reasonable time.

Now, it would be a better idea to send a fleet of probes rather than just one. NASA used to think that way, sending twin missions to Mars (Viking) and to fly past Jupiter and Saturn (Voyager).
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August 26th, 2016 at 11:50:43 AM permalink
Pacomartin
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Quote: Nareed
0.05c is 1/20th the speed of light. If we can achieve this, it would still take the probe 100 years or so to get there (4.5 light years times 20 plus acceleration times; deceleration would occur at the destination).


This initiative is talking about 0.25c or closer to 20 years. But the probe would only weigh a few grams. If it can send back a signal at speed of light, then 24.5 years to get a return.

https://breakthroughinitiatives.org/Initiative/3
August 26th, 2016 at 12:08:15 PM permalink
Nareed
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Quote: Pacomartin
This initiative is talking about 0.25c or closer to 20 years. But the probe would only weigh a few grams.


I like the buckshot idea. Send so many probes, a few are bound to make it.

I'd worry about what radiation would do to the probes at that speed. That is, when they collide with stray atoms and particles at 25% the speed of light, that can cause physical damage in addition to secondary radiation from such collisions.

I'm also concerned about communications. It's no use sending one or one million probes to Proxima if they can't report back, right? A sizable probe can carry a high-gain antenna and a powerful transmitter. What will the nano-probes have? What data transfer rate will they be capable of? We'll be waiting an additional 4.5 years for reports after the probes reach Proxima. Imagine if we add weeks to that for the data to come in.
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August 26th, 2016 at 1:10:30 PM permalink
rxwine
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Quote: Nareed
A sizable probe can carry a high-gain antenna and a powerful transmitter. What will the nano-probes have? What data transfer rate will they be capable of? We'll be waiting an additional 4.5 years for reports after the probes reach Proxima. Imagine if we add weeks to that for the data to come in.


Self-assembling technology might be prove useful.
You believe in an invisible god, and dismiss people who say they are trans? Really?
August 26th, 2016 at 1:18:41 PM permalink
Nareed
Member since: Oct 24, 2012
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Quote: rxwine
Self-assembling technology might be prove useful.


I'd buy that if each nanoprobe is a piece of one type that can fit with pieces of other types. Otherwise, not so much.

On the other hand, not much has been done to test and develop solar sails. I really don't think anyone with the capital, influence or power to affect these things has ever seriously considered an interstellar trip of any kind.

If there is a planet around Proxima, or even better more than one, and if we find any hint of positive or ambiguous life markers (ie oxygen in the atmosphere), we will see real, practical consideration given to a serious means of getting a probe there.
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