You might know why the sky is blue, but why isn’t the sky violet?
The interaction of light and glass is extraordinarily complex, as you can see in the video above.
One of the great things about science is how we keep testing our assumptions. Even when a phenomenon has been rigorously tested, we still push the limits of observation. Take, for example, some recent research on the speed of light.
The inherent speed of light is built into the very nature of what light is. Since the fundamental leptons and quarks that comprise matter have electric charge, they are also subject to the fundamental nature of light speed. All the strange aspects of time dilation and warped gravity work in such a way that the speed of light is always preserved.
After making a successful landing on 67P/C-G, the Philae probe gathered as much data as it could before entering “sleep mode.” It’s not clear at this point whether it will revive again. While the ESA team had hoped Philae would have remained active longer, the lander did complete all of its major data gathering, so we can call this a win. The reason Philae went into sleep mode is that it happened to land in the shadow of a cliff, which meant it wasn’t getting enough exposure to sunlight to keep its batteries charged. Like many spacecraft, Philae is solar powered. It needs light to keep going.
The supermassive black hole in the center of our galaxy, known as Sagittarius A*, is pretty quiet for a black hole. It does however flare up from time to time, when material is captured, as can be seen in images from the NuSTAR x-ray telescope. Of course, x-ray astronomy with enough sensitivity to observe x-ray flares at galactic center is …
There’s been a bit of press regarding “missing light” in the universe. It all starts with a recent paper in the Astrophysical Journal Letters. Most of the popular articles spin things as missing light because that was the spin of the press release, but the actual work is more subtle, and more interesting.
A paper has recently been published in the New Journal of Physics claiming that the speed of light is wrong. This has triggered the usual headlines in the popular press, but as the saying goes, “extraordinary claims require extraordinary evidence.” So let’s look at the evidence behind this paper.
One of the properties of atoms and molecules is that they interact with light in an interesting way. If you heat up atoms or molecules in a gas, they will give off light. But they only give off light at specific wavelengths (colors).
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