KIC 8462852 Faded Throughout the Kepler Mission
arxiv.org6 pointsby throwaway_yy2Di1 comments
...tidally locked, possibly losing their water and
atmosphere in tens or hundreds of millions of years.
Can we directly image the planet from earth?
1. "The planet/star contrast is 10^-7 " This basically means
for every 10,000,000 photons from the star, we would measure
~ one from the planet.
2. "Current instrumentation using adaptive optics and
coronography on 10 m class telescopes (like Sphere on VLT or
Gemini Planetary Imager) aims at achieving a contrast of
10^-6 to 10^-7 at an angular resolution of 100-200 mas"
3. "The planet has a separation of 38 mas".
4. Therefore with the best planet imagers we cannot
currently directly image the planet. Our best hope is the
E-ELT which should have first light in 2024.
However, there is reason to hope that the even larger
European Extremely Large Telescope will have enough
resolution (about 5e-8 radians? hard to tell from their
official publications)
The planet is about 0.05 AU from Proxima Centauri, meaning
we need an angular resolution of about 1.9e-7 radians to
even distinguish it from its host star. Is that realistic?
can it be easily ruled out?
ListPlay@ Flatten@ NestList[
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RandomReal[1.0, {80}], 100]
If you are the first almost live form, you have plenty of
time, and can evolved in an environment that has plenty of
food. Something like the brown goo of Titan, with lots of
hydrocarbons and other small molecules that you can pick up
for free.
I think what will really help us to get at a better estimate
is to answer the question whether there exists life in our
solar system that evolved independently of that on Earth.
Some have postulated the existence of a 'shadow biosphere'
on Earth, teeming with life that has gone undiscovered
because scientists simply don't know where to look. It could
contain life that relies on a fundamentally different
biochemistry, using different forms of amino acids or even
entirely novel ways of storing, replicating and executing
inherited information that do not rely on DNA or
proteins. [...] The trick is deciding what to look for and
how to detect it. The usual way that researchers search for
new organisms — by sequencing DNA or RNA — will not pick up
life that does not depend on them.
...We could even be oblivious to unfamiliar forms of life
right under our noses...
Specifically, unless the probability for evolving a
civilization on a habitable-zone planet is less than one in
10 billion trillion, then we are not the first. [...] In
other words, given what we now know about the number and
orbital positions of the galaxy’s planets, the degree of
pessimism required to doubt the existence, at some point in
time, of an advanced extraterrestrial civilization borders
on the irrational.
There's no known tractable way to solve chess. There's something like 10^120 move orders [0], and no known way to find perfect play without brute-forcing (almost) all of them. Chess engines can't solve to to the end of a game to see which moves are certain to win; they can only explore to a very shallow depth, and evaluate the horizon nodes by very human-like [1] approximate heuristics.
It looks perfect from a human PoV (the best human players have no chance of winning); but there's still an unimaginably large gulf between chess engines and mathematically perfect chess.
[0] https://en.wikipedia.org/wiki/Shannon_number
[1] https://github.com/official-stockfish/Stockfish/blob/master/...