(01-11-2024, 04:04 PM)SomeJackleg Wrote:(01-11-2024, 03:46 PM)Ninurta Wrote: The nearest star external to the solar system is 4.3 light years away (Proxima Centauri) and it's a red dwarf star, generally considered unsuitable for life as we know it. Planets within it's "goldilocks zone" would be close enough to the star to be tidally locked to it, as the moon is to Earth. That means it would have one permanently sunlit side and one side in perpetual darkness. Alpha Centauri, which Proxima orbits around, is a binary star, and is about 5.5 light years away.
that is habitablewhat was i thought. but there are some that say Proxima Centauri b sometimes called Alpha Centauri Cb some say it maybe habitable, it's others say it is not.
First, I need to make a correction - Alpha Centauri is about 4.5 light years away, not the 5.5 light years I typoed in there.
While I do beieve an exoplanet has been discovered around Proxima (ALF CEN C), I've not really studied the system in any sort of detail.I don't know the orbital distance, or whether or not Proxima is a "flare star". Speaking in generalities, M-class stars or "red dwarves" as Proxima is have small habitable zones around them because of their weaker radiation and temperatures. A planet close enough to be in the habitable zone will almost always also be close enough to be tidally locked to the star, leaving one side permanently facing the star and the other side permanently facing away from it, creating a hot side and a cold side. There has, however, been some discussion as to whether a narrow habitable band might be created on the planet in the terminator or "twilight zone" between the day and night sides of the planet.
Then there is the matter of solar flares to consider. Many red dwarfs are flare stars, and have violent outbursts at irregular intervals that would sterilize any planets within range of the flares, which distance generally includes the habitable zone around M class stars. Closer to the star, as is necessary to be in the habitable zone for red dwaves, also means more danger to the planet.
So, while it may be technically feasible for life to exist on a planet around Proxima Centauri, it has a pretty low probability. What's more important as regards this video is the resolution of the JWST vs. the distance to Proxima and the angular size both star and planet present back here on Earth. I don't think we yet have technology to bring the planet to resolution enough to show any detail at all, however fuzzy. That would probably require several JWSTs in a space-based wide interferometer array, I'm not sure that even a planet-wide interferometer would approach that resolution. It would probably take a wider baseline for the interferometer than the diameter of the Earth could provide, even if atmospheric interference could be cancelled.
This "discovery" was claimed to be at a distance of 7 trillion miles, but the closest known star, Proxima Centauri, is located at nearly 30 trillion miles away, quite a bit farther than the claimed discovery. I don't fault the writers for not knowing that, nor do I fault any readers for not knowing it. Most folks just don't understand the vast distances involved in astronomical matters. They usually don't have to, because someone else tells them distances in "light years", which some folks can make use of by using familiar units to cover the discrepancies. If a distance is reported in familiar, but seemingly huge, numbers, most folks just don't have the wherewithal or inclination to make the conversions to verify them. They wouldn't know, for example, that a "light year" is roughly 6.9 trillion miles, so a report of "7 trillion miles away" would seem to them to be huge, but making the report as "about 1 light year away" would show the improbability of the report right away.
I only know these things because astrophysics is what I studied at university, with a concentration on interstellar distances and mapping and navigating the same. It's not something most normal folks think about on a daily basis, so there is no fault in folks who don't realize the intricacies involved. They know other things I have no clue about, things that make my lifer easier without ever realizing it.
.