# Search results

1. ### Curvilinear... isn't that a strange word?

Hi PF. I'm over ten years out from graduate school in physics, and I still enjoy re-reading my textbooks. I came across the word curvilinear, and thought how strange a word it is; a juxtaposition of curved and linear, which are at times understood to be opposites. The textbook was describing...
2. ### Stargazing M - M as the distance modulus, and a question about the distance ladder

I'm attempting to understand fully the distance ladder we use in astronomy to determine the distance to stars that are too far away for parallax to work. I understand we calibrate to a standard candle data of period vs luminosity for the cepheid variable stars in a group. Then from knowing the...
3. ### What is the total amount of paving in the US?

While commuting I'm listening to The Great Courses "How the Earth Works" lecture series, and in one lecture the professor stated that the amount of paving (asphalt on the ground, buildings, concrete, etc.) in the United States is now greater than the area of the state of Ohio. The lectures were...
4. ### Misc. Getting used to new house, but what's best for noise elimination?

So, my wife and I really like our new house, but after living in it for two months we desire to find a smart way to deaden the noise. You see, our previous house was smaller, had carpet mostly, and did not reflect the noise inside near as much as this new house. Our new house is larger, has...
5. ### Possible to calculate the strength of a nuclear explosion from a photo?

Details of this calculation from the photo?
6. ### B Radon testing my first basement (already has a mitigation system)

Hi PF: The house my wife and I purchased recently is our first one with a basement and it already has a radon mitigation system installed. Unfinished basement. I've sent my short-term test to the lab and I have a long-term test that I intend to start this week. Do any PF members have any...
7. ### I Details in calculations from 19th century astronomy

I’ve read that Urban LeVerrier was able to calculate using Newtonian mechanics the precession of the perihelion point of Mercury’s orbit (1859). Is there a website or paper that shows the calculation in detail? In particular: How would one decide on the distance between Mercury and the other...
8. ### I Question about stellar nucleosynthesis from a non-expert

Given that the universe is 13.8 billion years old and our solar system is 4.6 billion years old, less than 10 billion years of star birth, life, and death is necessary to produce the heaviest occurring natural elements. Given what we know about supernova, what is the minimum number of supernova...
9. ### Hurricane Rotations

Here's a question I want to ask a physicist: Is it possible for a hurricane in Earth's northern hemisphere to have sufficient linear momentum (directed South) to cross Earth's equator and still persist as a CCW-rotating hurricance but in the southern hemisphere? If so, for approximately how much...