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Thrilling Discovery of Seven Earth-Sized Planets Orbiting Nearby Star (theguardian.com)
At a press conference on Wednesday, NASA scientists announced that they have spotted seven Earth-sized planets orbiting closely around a small, ultra-cool star. The star is 39 light years away. From a report on The Guardian: It is the first time that so many Earth-sized planets have been found in orbit around the same star, an unexpected haul that suggests the Milky Way may be teeming with worlds that, in size and firmness underfoot at least, resemble our own rocky home. The planets closely circle a dwarf star named Trappist-1, which at 39 light years away makes the system a prime candidate to search for signs of life. Only marginally larger than Jupiter, the star shines with a feeble light about 2,000 times fainter than our sun. "The star is so small and cold that the seven planets are temperate, which means that they could have some liquid water and maybe life, by extension, on the surface," said Michael Gillon, an astrophysicist at the University of Liege in Belgium. [...] While the planets have Earth-like dimensions, their sizes ranging from 25 percent smaller to 10 percent larger, they could not be more different in other features. Most striking is how compact the planet's orbits are. Mercury, the innermost planet in the solar system, is six times farther from the sun than the outermost seventh planet is from Trappist-1.
How about: Bashful, Doc, Dopey, Happy, Sleepy, Sneezy and Grumpy?
Well yes, much in the same way one infers the presence of a stream of electrons from an electrical charge or the Big Bang from the CMBR, relative proportions of hydrogen, helium and lithium in the Universe and the red-shift of distant galaxies. Even a particle accelerator like the LHC at CERN does not in fact directly image subatomic particles. For chrissakes, what you "see" isn't a raw image, but is heavily processed by your nervous system, beginning right at the retina itself, then by the optic nerve and then by visual centers in the brain. In other words, what you "see" isn't actually the photons that the physical structures of the eye captures.
Lots of science is inference, seeing as many phenomenon cannot be directly observed. If you're saying inference is somehow questionable, then you're basically calling all form of observation questionable.
The world's burning. Moped Jesus spotted on I50. Details at 11.
I think that greatly depends. Without a strong magnetic field, the Earth would look a lot like Mars, with much of its ancient primordial atmosphere blown away. I can imagine if one or more of those planets do indeed have a strong magnetic field, then I don't see how it is improbable that they could not harbor life. At the moment, we can't even declare with a high degree of assurance that Mars does not host life.
The world's burning. Moped Jesus spotted on I50. Details at 11.
Anyone note how similar this system is to the solar system in Firefly?
Finding that many Earth-sized rocky bodies orbiting a star just 39 lightyears away, with the possibility that some of them may be able to have liquid water on their surface doesn't excite you? Did you have your sense of wonder and curiosity surgically removed?
The world's burning. Moped Jesus spotted on I50. Details at 11.
These were found using the transit method, which measures a star's reduction in it's brightness as something passes in front of it.
They know that these sorts of occurrences are not things like sunspots because they can follow up using measurements of the wobbling of the star due to the gravity the planets exert on it.
Combine the two and you have a reasonable inference that there are planets orbiting this star.
If these are not planets, given the above two types of evidence correlating with each other, what else could they be?
Chimay be right, chimay be crazy..
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This is a red M class Dwarf star. The lack of radiation is the more immediate concern rather the excess of it. Red M class dwarf stars emit most of their radiation as infra-red, and barely emit any ultraviolet. If ultraviolet radiation is indeed a requirement for life, then this will be a problem. Total sterilization is unlikely, since the amount of energy hitting the planets will likely be similar to what the Earth is already getting.
Also, wrt tidal locking, the main concern would be that one side of the surface will be boiling while the other side will be freezing (one side gets all the sun, the other side gets none), which IS a concern wrt. life. Earthquakes are not a direct effect of tidal lock. That would be geological activity.
Of course, all of this is conjecture. We need to study these kinds of planets a bit more to know for sure. Hence, their importance.
Your guide to distant worlds:
http://i.imgur.com/6jp4DVK.png
Mars first. No need to run before you can crawl.
Though so far our record is to crawl to the moon, feel proud, then crawl back down our hole and declare the rest of the universe isn't that good anyway.
Flawed! I don't know what "consentual" means, but surely don't rely on ASKING when determining if an alien is old enough. The alien I fucked SWORE to me it was 22, then I find out it's planet circles its sun every 90 MINUTES!
No seriously, we should set up a very large synthetic aperture array of telescopes on the far side of the moon to look at these and similar promising exoplanets in high resolution and spectroscopically etc.
Yes. I know the far side of the moon isn't always dark, but half the time it is, and is shaded from Earth's light and our EM emissions etc.
Where are we going and why are we in a handbasket?
That's where God keeps Earth's backups.
I wonder how far back the oldest goes?
Table-ized A.I.
Strong XUV irradiation of the Earth-sized exoplanets orbiting the ultracool dwarf TRAPPIST-1
https://arxiv.org/abs/1605.015...
Government cannot make man richer, but it can make him poorer. - Ludwig von Mises
You're missing a rather important detail there that makes your claim essentially meaningless: time.
We've already launched a few probes that, had we chosen to aim them correctly, would eventually have reached a nearby star system. Sure, Voyager 1 would take ~17,900 years to cross the 4.2ly to Proxima Centauri, but it would so with paltry energy consumption and far less efficient propulsion systems.
Granted, that's probably too slow to interest anyone in making the trip, and the energy requirements increase dramatically as you travel faster, but that's why most near-term plausible speculation assumes (non-FTL) travel between stars would be in generation ships - it's a much easier problem to solve if you're willing to take a century or three to make the trip.
Of course that's a long time to keep a relatively small closed ecosystem healthy, so we'd probably want to wait until we had a century or two of experience building and maintaining long-term viable space stations before we even attempted it.
Also, you talk about the "total generation capacity of the world's electrical grid" as though it's some sort of meaningful indicator about future energy producing capability. In fact though, that's not even a tiny fraction of the energy we're already adding to the Earth today - the CO2 released into the atmosphere by burning fossil fuels captures about a million times more energy than was generated by the power plant.
--- Most topics have many sides worth arguing, allow me to take one opposite you.
One thing you're forgetting is that these stars have very low gravity, so when they throw flares they get a lot further out into space than they do on the sun. Typically the incident radiation will be low for the reasons you described, but when a planet orbits through a flare it gets zapped really hard. Meanwhile, orbiting the sun, we are so unaffected by flares that when we saw one, we thought it was the Russians jamming our radar.
People who get excited about aliens living on planets orbiting dwarf stars are kidding themselves. These stars are a dime a dozen and make up more than 90% of all stars, their light is more strongly affected by planetary transits, and they tend not to gobble up their innermost planets when forming. It's no wonder we find exoplanets around them all the time. But there is nobody interesting living on any of them. You can really only trust type F and G stars with life. Larger stars explode so fast their planets haven't even had time to solidify, and smaller stars have to be hugged so closely that the planet is affected by the star's fickle weather patterns.
You can see the figures here for free --- and they provide much of the meat of the study.
http://www.nature.com/nature/j...
Michael Richmond "This is the heart that broke my finger."
mwrsps@rit.edu http://stupendous.rit.edu
Where are you getting "a few percent" from?
There's only 400ppm total CO2 in the atmosphere, that 100ppm represents fully 25% of the total.
Perhaps you're thinking of the fact that CO2 is only a few percent of the total atmosphere? But that's largely irrelevant because almost all atmospheric gasses are completely transparent to thermal infrared radiation, and so don't provide any insulation at all. If they were the only things in the atmosphere the Earth would be as cold as the moon (colder actually, the moon is actually coal black and thus a good thermal absorber)
Water vapor, CO2, and methane are responsible for the overwhelming majority of Earth's atmospheric insulation. Water makes up about 0.4% of the atmosphere (mostly at low altitude), CO2 is about 0.04% of the atmosphere,and methane 0.0002%.
Water is obviously the biggest contributor, but it can't build up in the atmosphere since it rains out as the concentration builds, so it remains fairly constant at a given temperature. It's worth nothing though that it acts as a positive feedback system - the warmer the planet, the more water vapor builds up in the atmosphere, and the more heat will be trapped. So it will tend to make any global temperature changes more extreme.
Methane is actually a considerably more powerful greenhouse gas than CO2 per pound, but there's so little of it that it still only traps a fraction as much heat as CO2. It's also worth mentioning though that humans are estimated to be responsible for somewhere around 2/3 of global methane emissions - we're working hard on that front as well.
Which leaves CO2 as a sort of "thermostat" - more CO2 leads to a warmer planet and faster plant growth, which pulls CO2 out of the atmosphere leading to a cooler planet and slower plant growth, which lets CO2 build up in the atmosphere again... it's a self-stabilizing system that oscillates around some "average" point until something disrupts it - such as dumping carbon into the atmosphere that's been locked underground for millions of years.
As for what difference a few percent can make? Lets do some rough math. Say CO2 is responsible for about 10% of the total greenhouse gas "insulation" (I have no idea, but it makes up about 10% of the total greenhouse gases in the atmosphere so that seems like a good guess). The 100ppm increase would therefore be responsible for about 2.5%. That means the Earth will have to warm up enough to radiate 2.5% more heat in order to shed the same amount of energy through the insulation to restore the energy balance and stop heating up. The amount of heat radiated is proportional to the fourth power of temperature, so a 2.5% increase in radiant heat translates to ...1.025^(1/4) = 1.006... a 0.6% increase in temperature. Earth currently averages about 61F, or 289K in absolute terms, and a 0.6% increase of that translates to 1.8K, or about 3.2F.
A three degree increase doesn't sound terribly catastrophic all on it's own, but that's assuming nothing else changes, which isn't the case.
First off as things warm up we'll have more water vapor in the air, further increasing the amount of insulation.
More dramatically, the warming isn't uniform - the poles are heating much faster than the rest of the planet, which means those shiny white ice "mirrors" that currently reflect sunlight back into space before its absorbed are being replaced with dark sunlight-absorbing water. That means the planet is absorbing more energy from the sun, and it's going to heat up even further until it's radiating all that extra energy back into space as well.
And of course there's the rising oceans to contend with: water has a coefficient of expansion of 0.00012/*F, and the oceans have an average depth of about 12,100 feet. 12,100feet x 3.2*F x 0.00012/*F = 4.65 feet. So even without any icecaps melting, the ocean would rise that much. Which maybe doesn't sound too terrible, but something like 90% of the worlds population live within 10 feet of sea level. That's going to b
--- Most topics have many sides worth arguing, allow me to take one opposite you.