::)
So the interwebs are atwitter this weekend and past week, with the discovery of what (due to its orbital characteristics) is most likely a rocky planet orbiting close around Proxima Centauri, our nearest known solar system. (Discovered or maybe distance-located after Alpha Centauri, due to the star's relative dimness and size, which will be a factor soon.)
Instead of announcing that a Mercury-like planet has been (probably) detected in the Proxima system, well shoot that don't market well. So IT'S THE CLOSEST EARTHLIKE PLANET TO US EVAR GUYZ!
Of course the problem is that it's ludicrously close to its star, but the star is relatively weak enough that it might not be cooking the surface like on Mercury so liquid water could, in theory, exist in small amounts. Somewhere.
But unless its rotational/orbital characteristics are completely different from anything else we've discovered or astrocalc'd up theoretically, it either has no day-night cycle at all, or a weird day-night cycle like Mercury (two cycles every three orbits around the star, with an 11 day orbit for Proxima b) -- so, very different in fact from Earth.
Really, it's only similarity to Earth is that it's probably a rocky planet about 1/3 our mass: gas planets are usually the close ones in, our solar system being a rare exception (the new mechanics not being at all well understood for why we'd have so many gas planets so far out and so many rocky planets so close), but at that distance even Proxima's relatively weak gravity pull would likely rip a gas planet apart quickly, especially one so much less massive than us (if such a gas planet could even exist -- I've honestly never heard). So it's probably rocky, in a broad temperature range that doesn't in itself immediately exclude liquid water, and that's the total limit of how Earthlike this planet is. Ah well.
http://www.skyandtelescope.com/astronomy-news/exoplanet-found-around-proxima-centauri-2408201623/
Astronomers have discovered a planet in the habitable zone of the closest star to the Sun.
Whether Proxima Cen b actually is habitable remains a wide-open question. Technically it lies at the right distance from its star that, if it has the right composition and atmosphere, it would be the right temperature to sustain liquid water on its surface.
No mention of Earthlike in this scientific article.
By the way : Alpha and Proxima Centauri are both stars of the same system.
It is actually a triple-star system (bound together by gravity). Alpha Centauri A and B are two bright, closely orbiting stars with a distant, dim companion, Proxima Centauri. The inner binary appears to the unaided eye as a single star, the third brightest in the night sky, but it lies 4.37 light years from the Sun. Proxima Centauri alone claims the honor of being our true nearest stellar neighbor at only 4.24 light years away.
I think we all know who lives there
(https://www.grogheads.com/forums/proxy.php?request=http%3A%2F%2Fdevil.oshinchan.com%2Fscreencaps%2FBabylon5%2Fmidnight23.jpg&hash=ae1d6fb5638c67906326058efa0cea9e22233a7b)
If our universe is anything like a 4x game pirate ships are already on the way to Earth.
Quote from: bbmike on August 29, 2016, 07:59:08 AM
If our universe is anything like a 4x game pirate ships are already on the way to Earth.
If they can keep Hillary out of the White House, I welcome our new alien overlords.
Quote from: mirth on August 29, 2016, 07:46:15 AM
I think we all know who lives there
...restraining.... geek.... commmeennnntttttt.....!
Quote from: bbmike on August 29, 2016, 07:59:08 AM
If our universe is anything like a 4x game pirate ships are already on the way to Earth.
Yep, on reading the news (even after cynically fact-checking it ;) ), I immediately wanted to fire up a game of
Sword of the Stars or
Distant Worlds: Universe! sigh. :smitten:
Quote from: JasonPratt on August 29, 2016, 08:13:09 AM
Quote from: mirth on August 29, 2016, 07:46:15 AM
I think we all know who lives there
...restraining.... geek.... commmeennnntttttt.....!
Dammit! You saw through my attempt to get you to expound on how the Centauri aren't from the Alpha Centauri system :P
I had it typed up. I could only resist so far. It felt therapeutic. :))
You will notice I also refused to expound on the difference between Proxima and Alpha, although being quite the baroque operator I just mentioned it anyway... :P
Quote from: JasonPratt on August 29, 2016, 08:21:11 AM
You will notice I also refused to expound on the difference between Proxima and Alpha, although being quite the baroque operator I just mentioned it anyway... :P
Well played, sir. Well played.
Quote from: JasonPratt on August 29, 2016, 06:21:06 AM
Really, it's only similarity to Earth is that it's probably a rocky planet about 1/3 our mass: gas planets are usually the close ones in, our solar system being a rare exception (the new mechanics not being at all well understood for why we'd have so many gas planets so far out and so many rocky planets so close), but .....
<snip>
Keep in mind the reason for the large majority of discovered exoplanets being huge gas giants, many of which orbit closely around their star - the methods being used to find them.
They're measured either by dips in light output when a planet crosses in front of the star (the Transit Method), or by the gravitational wobble an exoplanet has on the parent star while circling it.
Both methods generally only find very large/massive planets, in relation to the parent star, due to those detection methods. However, they don't need to be as quite as massive when they're in close orbits.
Simply put, these two main methods, which have been the source for nearly all exoplanet detections, is heavily skewed towards finding large gas giants, planets in very close orbit, and especially a combination of the two. Rocky planets aren't detected as often because many wouldn't have enough mass, or orbit close enough, to be found yet.
The overall picture is still very incomplete regarding exoplanetary system make-up. We just don't have the capability to detect every possible planet around any other star.
The "Breakthrough Starshot (http://breakthroughinitiatives.org/Initiative/3)" project might...MAYBE...allow us to visit other stars within our lifetime. If it's not utter BS. And we live a long, long, long time.
Long story short, it's a proof-of-concept project where they hope to build unmanned probes that can travel at upwards of 20% of the speed of light, getting them to Proxima Centauri within 20-30 years or so. I think they were saying that they might possibly be able to launch the first probe by 2036.
So if they keep to their timetable (hahahahaha), it'll be 2056 to 2066 or so before our Earth probes reach Proxima Centauri. I don't hold out hope that I won't be senile by then, if I'm even alive still.
And add another 4.5 years for any signal to get back to us ...
even faster way to check exoplanets for atmosphere composition ....and a nice picture for the media also in the package
a occulter floating in space block the central star and a space telescope (that could be a dedicated or the planed replacement for Hubble which will get launched 8/2018 anyway) capturing the dim exoplanets radiation.... and its only $750Mio for the starshade occulter
https://en.wikipedia.org/wiki/New_Worlds_Mission
Quote from: Pete Dero on August 31, 2016, 06:07:05 AM
And add another 4.5 years for any signal to get back to us ...
Meant to mention that. O0
Quote from: Nefaro on August 30, 2016, 07:38:24 PM
Keep in mind the reason for the large majority of discovered exoplanets being huge gas giants, many of which orbit closely around their star - the methods being used to find them.
True, although I think there are also theories for why gas giants
ought to be closer and rockies farther out.
But you're also right, the current detection technology skews a particular direction.
Quote from: JasonPratt on September 02, 2016, 12:12:37 PM
Quote from: Nefaro on August 30, 2016, 07:38:24 PM
Keep in mind the reason for the large majority of discovered exoplanets being huge gas giants, many of which orbit closely around their star - the methods being used to find them.
True, although I think there are also theories for why gas giants ought to be closer and rockies farther out.
But you're also right, the current detection technology skews a particular direction.
It's certainly shown Planetary Migration to be a common thing, and supports the very solid theory of it happening in our own system. O0
A big question is how often do planets or, more specifically, rocky planets get ejected from their system by the migration of their larger brethren. We supposedly lost one when Jupiter moved inwards & then back out due to an orbital resonance with Saturn, and switching Uranus and Neptune. Thanks for saving Earth, btw, Saturn. I wonder whether the "ejected" planet is the predicted "Planet 9", in extremely distant orbit, or whether there was also another that is completely gone.
I think we'll slowly start seeing rocky planets being discovered in close orbits more often as better technology comes online. The one around Proxima is right next door to us, galactically speaking, and very close to a relatively smaller dwarf star, making it easier for our current methods to detect.
Quote from: JasonPratt on September 02, 2016, 12:12:37 PM
Quote from: Nefaro on August 30, 2016, 07:38:24 PM
Keep in mind the reason for the large majority of discovered exoplanets being huge gas giants, many of which orbit closely around their star - the methods being used to find them.
True, although I think there are also theories for why gas giants ought to be closer and rockies farther out.
But you're also right, the current detection technology skews a particular direction.
On of the most used method (transit of planet in front of star) tendq to favor detecting gas giants in close orbits. The fact that many of these are detected does not mean
they are the most common configurations. As research continues gas giants further from their stars will start showing up more often. You need a longer observing period to see a transit happening as their orbits will be bigger and take longer to complete.
Some recent info : http://www.skyandtelescope.com/astronomy-resources/kavli-qa-how-did-planets-form/
Quote from: Nefaro on September 02, 2016, 02:14:40 PM
We supposedly lost one when Jupiter moved inwards & then back out due to an orbital resonance with Saturn, and switching Uranus and Neptune. Thanks for saving Earth, btw, Saturn. I wonder whether the "ejected" planet is the predicted "Planet 9", in extremely distant orbit, or whether there was also another that is completely gone.
There are some interesting if half-baked theories about Saturn having migrated in far enough at one point to drag Mars, Venus, and Earth along in its wake, leaving geographical scarring common on Mars and Earth (maybe also Venus, harder to tell) due to electrical arc discharges.
That all sounds plausible enough; the half-baked side argues that this happened during the last four or six thousand years! -- even up into the last 3000 years maybe :o -- and that although this didn't last long (a couple of generations, perhaps less) the spectacular effects contributed to a bunch of mythical and partially historical culture around the globe.
Quote from: JasonPratt on September 12, 2016, 11:23:34 AM
Quote from: Nefaro on September 02, 2016, 02:14:40 PM
We supposedly lost one when Jupiter moved inwards & then back out due to an orbital resonance with Saturn, and switching Uranus and Neptune. Thanks for saving Earth, btw, Saturn. I wonder whether the "ejected" planet is the predicted "Planet 9", in extremely distant orbit, or whether there was also another that is completely gone.
There are some interesting if half-baked theories about Saturn having migrated in far enough at one point to drag Mars, Venus, and Earth along in its wake, leaving geographical scarring common on Mars and Earth (maybe also Venus, harder to tell) due to electrical arc discharges.
That all sounds plausible enough; the half-baked side argues that this happened during the last four or six thousand years! -- even up into the last 3000 years maybe :o -- and that although this didn't last long (a couple of generations, perhaps less) the spectacular effects contributed to a bunch of mythical and partially historical culture around the globe.
Sounds pretty far-fetched, but you can't rule anything out until disproved.
I was mentioning one of the most popular planetary migration theories for our system, in which Jupiter's early migration had a direct effect on our inner rocky planets being fairly small. Along with numerous other notable effects. An interesting one.
The "Grand Tack" theory ->
http://www.space.com/28901-wandering-jupiter-oddball-solar-system.html
QuoteWandering Jupiter
The researchers modeled a leading scenario for the formation of Jupiter and Saturn known as the "Grand Tack," wherein Jupiter arose first and migrated toward the sun until Saturn formed, which caused Jupiter to reverse course and migrate outward to its current orbit. They calculated what might happen if a set of rocky planets formed in the inner solar system before Jupiter migrated inward. [Photos of Jupiter: The Jovian Giant]
In the early solar system, the sun was surrounded by a dense disk of gas and dust. This suggests that any inner rocky planets forming might have eventually become super-Earths such as many of the exoplanets that astronomers have seen around other stars.
However, as Jupiter moved inward, its gravitational pull would have slung these nascent inner worlds into close-knit, overlapping orbits. This would have set off a series of collisions that smashed these newborn worlds into pieces.
"It's the same thing we worry about if satellites were to be destroyed in low-Earth orbit," Laughlin said in a statement. "Their fragments would start smashing into other satellites and you'd risk a chain reaction of collisions. Our work indicates that Jupiter would have created just such a collisional cascade in the inner solar system."
The resulting debris would then mostly have spiraled into the sun. A second generation of inner planets would have formed later from the depleted material that was left behind. This would explain why Mercury, Venus, Earth and Mars are younger than the outer planets, and why they are both smaller and have much thinner atmospheres than inner worlds seen in other planetary systems.
"The results imply that our terrestrial planets formed after Jupiter's early migration wiped the slate clean and set the stage for formation of gas-poor objects," Batygin said. "The fact that all of these characteristics of the solar system turn out to stem from the same process is exciting — it is as if the scattered pieces of the puzzle are finally falling together into a coherent picture."
"This kind of theory, where first this happened and then that happened, is almost always wrong, so I was initially skeptical," Laughlin said in a statement. However, "there is a lot of evidence that supports the idea of Jupiter's inward and then outward migration. Our work looks at the consequences of that. Jupiter's 'Grand Tack' may well have been a 'Grand Attack' on the original inner solar system."
Who else thought of Orson Welles as Unicron when you got down to the Grand Attack of Jupiter? >:D