askscience

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When metal is hot enough to start emitting light in the visible spectrum, how come it goes from red to white? Why don’t we have green-hot or blue-hot?	4840
Is the density of interstellar space high enough to create measurable drag for a spacecraft moving at relativistic speeds?	113
Epidemiology question: do viruses compete for space. I.e. could inoculating populations against specific types of the flu virus mean that it'd be easier for a rare mutation not included in the vaccine to spread?	19
Why doesn’t the adhesive on a post-it note glob off onto a wall?	13
If we have the technology to image the handful of individual stars as they closely orbit around the black hole at the center of the Milky Way, why hasn't there been a concentrated effort to map all stars on our half of the Milky Way?	11
What evidence do we have that the constant speed of light in a vacuum was the same 1 billion years ago? Or 5 billion years, or even further in the past?	7
What are some techniques/technologies that humans can use to slow or prevent long term global warming and climate change? I've heard spraying dust into the atmosphere, seeding clouds, etc... Would any of this be even partially effective?	6
Proxima Centauri is the closest extrasolar star (4.2 light years) but is still too dim to be seen by the naked eye. How do we know dark matter isn't simply stars that are too dim to see but whose gravitational effects can be inferred?	5
Since human and unmanned spaceflight missions compete for resources, and the science from unmanned missions far outpaces the efforts of manned missions, what benefit is there to sending humans into space?	4
Will the Milky Way Galaxy effectively reach the Great Attractor in some form before the expansion of the universe accelerates to a point where it's no longer possible?	3

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