cornucopiaofmadness asked:

Why can radio and microwaves travel through space but sound can't?

Because sound waves are vibrational waves, while radio and microwaves are electromagnetic in nature.

Sound waves require a certain density of matter in order to travel and vibrate through. That’s why sound works on earth, but that doesn’t in space. There is an abundance of free molecules to vibrate through (molecules in the air). That’s how sound works by vibrating atoms and molecules.

But in space there are so little molecules available that sound waves cannot propagate.

Why electromagnetic waves can travel through space or a vacuum is more complicated and is a bit beyond my knowledge. But the gist of it is that, its because of wave particle duality and the fact that the particle involved is a photon. And photons do not require a medium to travel through.

If any physics people can elaborate or correct me, feel free.


Hummingbirds have a unique way of flying among birds. By flapping in a figure-8 motion, they generate lift on both the upstroke and the downstroke, which enables them to fly forward, backward, and even hover for extended periods. Such mid-air acrobatics are necessary for a species that feeds on flower nectar. What is especially impressive about the birds, though, is how they hold up even in adverse conditions like wind or rain. By placing birds in a wind tunnel and filming with high-speed video, researchers can see how hummingbirds maintain their feeding position even in 20 mph (32 kph) winds. By fanning out their tail feathers like a rudder, they can control their body orientation despite turbulent gusts. Not even rain stops them. The birds will periodically shake themselves dry, much like a dog if a dog could manage to fly while shaking itself. (Video credit: Deep Look; submitted by entropy-perturbation)

Why Physics Needs Philosophy

By Tim Maudlin

How can we understand the world in which we find ourselves? How does the universe behave? What is the nature of reality?….Traditionally these are questions for philosophy, but philosophy is dead. Philosophy has not kept up with modern developments in science, particularly physics. Scientists have become the bearers of the torch of discovery in our quest for knowledge. —Stephen Hawking and Leonard Mlodinow

This passage from the 2012 book “The Grand Design” set off a firestorm (or at least a brushfire) of controversy. Has philosophy been eclipsed by science in the quest for understanding reality? Is philosophy just dressed-up mysticism, disconnected from scientific understanding?

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Finally, a question about something important. My advice to any heartbroken young girl is to pay close attention to the study of theoretical physics. Because one day there may well be proof of multiple universes. It would not be beyond the realms of possibility that somewhere outside of our own universe lies another different universe. And in that universe, Zayn is still in One Direction.
—  Steven Hawking, when asked “What do you think is the cosmological effect of Zayn leaving One Direction and consequently breaking the hearts of millions of teenage girls across the world?”

awaitingtherain asked:

On the topic of EM waves propagating through space: How does signal strength play a role? For instance, if a radio signal from Earth reaches a planet 100 light years away, and say it is received by some indigenous intelligent species, would there be any sort of decay in the signal that would hinder their ability to decipher it? I ask this because I have always been under the impression that clarity of signal is dependent on its strength, although I only have a limited knowledge of how they work.

That’s beyond my knowledge of physics, but it is an interesting question.



The Darkness Surrounds Us

New York University particle physicist Glennys Farrar explains what evidence clued in scientists to the existence of dark matter, and University of Michigan astrophysicist Katherine Freese discusses gravitational lensing, one of the mechanisms scientists use to find dark matter in the universe.

Watch the full Program Here: The Dark Side of the Universe

By: World Science Festival.
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Neil deGrasse Tyson talks a bit about that Batman V Superman fight. Starts at 3:35.