Noname Given said:
And what would the probe tell us? Assuming we could accelerate it to 1/3 C; who would it break speed down to something that could be useful once it arrives in the 'neighborhood.
Who says a probe needs to slow down to do something useful? Look how much we've learned about our own system's planets from probes that were just passing by.
Of course a probe travelling at a high proportion of
c would be limited in what it would reveal, but even just a simple camera and spectrograph passing directly through the system, photographing its bodies up close and from different angles, would tell us tons more about it than we can discern from 4.3 light-years away.
Of course, a probe could potentially brake itself by deploying either a lightsail to be slowed by Alpha Centauri's light or a magnetic coil to brake against the interstellar medium. Also, for a long time there's been a proposal around for a lightsail probe driven by a laser beam from Earth; on nearing its destination, the sail would split into two concentric parts, with the outer part focusing light onto the front of the inner part, pushing backward on it to decelerate it.
Also; given it takes 8.6 years to do a round of commnication, how could/would we program it to find planets or other objects of interest.
If a single probe were used, it would have to have artificial intelligence, of course. But the Starseed proposal calls for sending thousands of tiny probes. I think the idea is to create an imaging/signalling array that could do the job the individual probes couldn't on their own, but a similar principle could be used to blanket the system with many fairly basic probes that, collectively, could gather all sorts of useful information.
As for finding planets, we probably won't need probes for that. The telescopes going up into space over the next decade or so should be capable of detecting planets around Alpha Centauri, if we don't begin finding them using existing methods first. By the time we got around to physically sending probes there, we'd probably already know where all its major planets are.
Dr.Trekyll and Hyde said:
Dayton3 said:
We don't even known if Alpha Centauri has any planets. Much less any in the habitable zone.
I thought we've detected planets in the Centauri system.
No exoplanets have been detected in the Alpha Centauri system yet, but as I said, if they're there, we'll probably find out within the decade. And there's been some pretty good simulation work done by Elisa Quintana et al., calculating the odds of planet formation in the system and the probable orbital range and number of planets. The simulations conclude that there could be 3-5 planets around Alpha Cen A and 2-4 planets around Alpha Cen B -- probably all terrestrial, because observations have ruled out anything Neptune-sized or larger, and because Jovian planet formation would probably have been disrupted due to the gravitational interactions within the binary system.
If that's correct, then the odds of there being at least one planet in the habitable zone of one of the stars are pretty high -- especially with two stars to choose from. And of course habitable planets aren't the only ones worth looking at. We could learn plenty about planet formation, geology, stellar evolution, and who knows what else by being able to compare planets in two different star systems rather than being limited to one. Just look at how much the 250-odd exoplanets detected over the past 15 years have overturned our past assumptions about the formation and evolution of planetary systems. And those are just the giant planets we're able to detect at great distances. There are whole populations of rocky planets, icy planets, maybe carbon planets, ocean planets, and other purely theoretical planet types waiting for us out there, and maybe even some types we've never thought of.
