I'm disappointed by the negativity expressed in some of the top comments in this thread. This is an exciting discovery, and the most popular comments here are basically "humanity is destroying its own planet, if this place was anything like earth, the inhabitants there would have already destroyed their planet."
NASA announces discovery of Earth-like planet with earth similarity index 0.98
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Re: NASA announces discovery of Earth-like planet with earth similarity index 0.98
#132It HAD an ESI of 0.98 1075 years ago. By now, the inhabitants have burned through all their fossil fuels and then annihilated each other with nuclear weapons leaving the planet in both a long-term nuclear winter and with a runaway greenhouse effect. Its ESI must be at least 1.0 by now.
I'm not sure what fossil fuels and nuclear weapons have to do with this but 1075 years isn't a very long time. There may not be intelligent life on the planet yet.
"There may not be intelligent life on the planet yet"
Sounds pretty similar.
Re: NASA announces discovery of Earth-like planet with earth similarity index 0.98
#133Earlier quoted context omitted.
A few zones some think need to overlap and be dialed-in to come close to offering a habitable place: water habitable zone ultraviolet habitable zone photosynthetic habitable zone ozone habitable zone planetary rotation rate habitable zone planetary obliquity habitable zone tidal habitable zone astrosphere habitable zone
I'd put magnetosphere in that list
I'd put it up fairly high on the list...
http://www.windows2universe.org/glossary/plasmaspheric_gain....
Re: NASA announces discovery of Earth-like planet with earth similarity index 0.98
#134ELI5: until we flew next to Pluto this month all we had is blurry 16-pixel images. How can we get such precise data on something millions of times further?
Nearly all of the ways we detect exoplanets involve indirect observation. Most of them are based on observing the star(s) in the system of the planet. The two main ways we detect exoplanets are: * Radial Velocity - just as the gravity of a star effects a planet's orbit, the gravity of a planet also has an impact on the star's. It's just this impact is extremely small. By measuring variations in a star's movement due…
"measuring variations in a star's movement"
Not sure what the primary means of doing that is, but I think it includes Doppler shift measurements of the star's light.
Re: NASA announces discovery of Earth-like planet with earth similarity index 0.98
#135I'm disappointed by the negativity expressed in some of the top comments in this thread. This is an exciting discovery, and the most popular comments here are basically "humanity is destroying its own planet, if this place was anything like earth, the inhabitants there would have already destroyed their planet."
It is the new norm of HN. Almost ever top voted comment nowadays is a negative swipe or a nit-pick that is tangentially related to the OP.
Re: NASA announces discovery of Earth-like planet with earth similarity index 0.98
#136ELI5: until we flew next to Pluto this month all we had is blurry 16-pixel images. How can we get such precise data on something millions of times further?
IANAAP, but I saw a similar question about how the Hubble space telescope could only get blurry pictures of Pluto. The answer was that it was akin to using a microscope as a telescope (or vice-versa), if that makes sense?
Not really. The problem isn't that Pluto is too close (Hubble has taken excellent pictures of Mars), it's that Pluto is tiny, specifically in angular size.
Re: NASA announces discovery of Earth-like planet with earth similarity index 0.98
#137ELI5: until we flew next to Pluto this month all we had is blurry 16-pixel images. How can we get such precise data on something millions of times further?
Distance, time, and amount of light. All these things come into effect. The reason why Pluto took so long? Imagine trying to read a magazine with a pair of binoculars vs. somebody taking a picture right next to it. Which do you think will be easier to read? We've had a pair of binoculars up in space for a while, but it was designed to see way further than Pluto. That is why we have always had blurry images.
We've had blurry images of Pluto because of its tiny angular size. The fact that its closer than some of the things Hubble has taken better pictures of is not relevant.
For example, here's a Hubble photo of Mars: https://milesobrien.files.wordpress.com/2010/08/mars_hubble....
Re: NASA announces discovery of Earth-like planet with earth similarity index 0.98
#138I sense a great disturbance in Hollywood like a screenwriter was just inspired to write something original...
Re: NASA announces discovery of Earth-like planet with earth similarity index 0.98
#139It HAD an ESI of 0.98 1075 years ago. By now, the inhabitants have burned through all their fossil fuels and then annihilated each other with nuclear weapons leaving the planet in both a long-term nuclear winter and with a runaway greenhouse effect. Its ESI must be at least 1.0 by now.
Even earth has survived 5000 years of civilizations with the last 200 at that level.
Problem is even with a probe at 10% the speed of light we'll never even see it.
Heck if it was 107.5 light years away it would still be "useless" but might inspire better telescopes.
Re: NASA announces discovery of Earth-like planet with earth similarity index 0.98
#140This similarity index only measures radius, density, escape velocity and surface temperature, so it doesn't mean nearly as much as one would think upon reading the headline
Does surface temperature imply an awful lot in this situation? How accurate are we able to measure?
> How accurate are we able to measure?
Quite poorly, I believe. I think surface temperature is estimated based on the distance from the star, and I think it assumes an albedo (reflection coefficient) and maybe a typical(?) atmosphere (though I'm not sure about this). In any case, I imagine the error's quite large.
Unfortunately, we only have our own solar system to go on, and until we find better ways of studying these exoplanets, we have no good way of knowing if the planets in our solar system are really representative of what's out there or not. But that's why this research is so important.