Recent content by smithpa9

Thanks! So, I guess my question is more generally, what are the implications of there being such a reference frame that is tied to the origin of the universe? It seems like that would be very important and meaningful, but I'm struggling to figure out exactly what the important implications are.

Thanks, Ibix! When you say that frame is hugely important because of all the matter that is at rest in that frame, what matter are you referring to? It's not clear to me that any particular galaxy, star, or planetary system need necessarily move exactly in sync with that reference frame. Are...

Studies of the Cosmic Microwave Background shows that the Earth is moving roughly 380 km/s with respect to it towards the constellation Leo I think. Yet (I think) the Cosmological Principle and the Michelson-Morely experiments suggest there is no preferred reference frame in the universe --...

My astronomy textbook includes this graph of the temperature of the Sun's Corona versus the distance above the photosphere. It appears to go up from 4,500 K to over 1 million K at 20,000 km above the photosphere. But at what point does it come back down? Or does it not? Does that mean the...

Thanks! That makes perfect sense.

Are the granules that we see on the Sun actually in the photosphere? Or are they actually just the top of the convection zone, with the photosphere beginning just above them? Or is the photosphere simply defined as the top edge of the convection zone where the granules are present, having...

If I understand correctly, orbital resonances of some of Saturn's moons are responsible for clearing out gaps in Saturn's ring structure (like the Cassini division). But I've also read that Neptune and Pluto are in a roughly 2:3 orbital resonance. So, do orbital resonances pull matter out of a...

About 20 years ago, in my mid-30s (and with a BA in economics and a master's in business), I started taking night classes in physics hoping to eventually earn the science degree I'd always wanted but never pursued. I found physics forums and used it to ask questions I was unable to get answered...

I think the answer for planets around the Sun and electrons around a nucleus are different. The answer above works for planets. Using the same classical mechanical answer, an electron should spiral into the center of an atomic nucleus in a tiny fraction of a second, unlike a planet around...

What do you find to be the most UN-intuitive (non-intuitive?) of classical physics (pre-QM and Relativity)? Most people find quantum mechanics and relativity very UNinuitive, because they involve phenomenon at subatomic scales or very high speeds, both of which are well outside a human...

I think Raza's question is more complicated (and fascinating) than the simple fact that objects that are close to you appear bigger than when they are far away. That's easily explained. Consider instead watching an airplane just before landing at an airport. I'm guessing it is probably...

Hmmm. . . I don't think this is quite right. The "shadow" you see on the moon that causes it to be a crescent is not the shadow of the Earth. It is simply the side of the Moon facing away from the Sun. It is the night-time side of the Moon. The only time a shadow of the Earth causes any...

Excellent. All good answers. Thank you.

I know the following statement to be true, being proven both mathematically, and verified by astronomical observations. What I need help understanding is HOW. . . "The law of Conservation of Angular Momentum requires that the slowing down of the rotation of the Earth around its axis caused...

Thanks! Good answers Rade and Colion. Thank you.