Earth Definition and 1000 Threads

Hello everyone, My name is Dani Rose. I recently joined because I am working on a series of essays about geology, continental drift, and astronomy. Through my research, I realized how important it is for scientists from different fields to work together. I believe this community is a wonderful...

Just a thought ... Given that the earths magnetic field has a stream of small changes, would a power transmission line forming a loop around the equator generate useful power ? Not exactly economic of course. Maybe just circumnavigating the arctic circle would be enough ?

Slow particles (solar wind) should come from a direction that is different than the direction photons come from: it takes slow particles more time to reach the Earth, therefore slow particles should be emitted earlier. Some calculations: - Sun diameter is about 1400000 km - solar wind speed is...

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Hi, Physics Forums https://en.wikipedia.org/wiki/Parker_Solar_Probe I haven't found any clue on Wiki, though this website is updated to two hours ago. I suppose this is not good news. Does anybody know anything? Love and Peace Marcos

I haven't really attempted anything worth showing on the calculus side

Observational Assessment of Changes in Earth’s Energy Imbalance Since 2000: 2024 Added greenhouse gases are supposed to be decreasing the OLR.

TL;DR Summary: For a transiting exoplanet, we find it takes 4.3 days from the start of the transit for the host star to reach a minimum brightness, which lasts for 10 days. Show that the radius of the exoplanet is about 1/2 of Earth’s radius if its orbital radial velocity is 17 m/s. I am...

At least for a little while https://www.sciencealert.com/earth-welcomes-a-new-mini-moon-later-this-month

"Matter tells spacetime how to curve, and curved spacetime tells matter how to move" Taking the above into account, the space on the Earth's surface is slightly curved. What is the radius of curvature of space on the Earth's surface due to its mass?

The usual approach for solving for the time it takes to fall to the center of the earth neglects air resistance & uses Hooke's Law. But if you solve it "the hard way"... Gme*m/r^2 = ma me = 4/3 rho pi r^3 G * 4/3 rho pi r = a separate variables, integrate twice r*Ln(r) - r = 2/3 G rho pi t^2 The...

TL;DR Summary: This is an astronomy application. Mentor note: Moved from a technical forum section, so the homework template is missing. How long does it take a beam of light to reach Earth from the Sun when the Sun is 93,000,000 miles from Earth? Express your answer in seconds, using...

A quasi-moon of Earth is a rock to that orbits both the Earth and Sun with the same solar orbital period as Earth.

How did you find PF?: via Google search Hi, I wonder if the shade from the sun on the ground, on a sunny day, is it a straight line or a curved line?? and if it is curved, how curvature can be calculated ?? Let´s say I have a pole or building, and I can follow up the shade of its top on the...

This is most probably a dumb idea as I'm far from deep physics knowledge but I was thinking. What if Earth is hot inside not because of the pressure and the radioactivity but because it's mass attracts particles (similarly to gravitational lensing) and they collide right in the Earth's center?

I'm trying to find how Cavendish got the density of the earth to 5,48 times the density of water. In all of the YouTube videos and webpages I have seen, they mention different formulas where the mass of the earth or the gravitational constant, G, is included. But as far as I understand, these...

I stretch my tendrils to say hello.

"bubbles are ball" is called isoperimetric problem in serious mathematic. In this topic, many essay were written. Here's my serious essay about "why earth ball", which has been rejected by arxiv and my mentors...... I would want to know if physicists are interest? I really think that is...

What would be the consequence if a powerful (1 Tesla) magnetic field came into proximity of Earth? Options open concerning size of generating body and distance. Thank You.

A NY Times article "Exactly How Much Life is on Earth?" (research article here, behind a paywall) says that there are about 1030 cells currently on earth and the total numbers of cells that will be on earth through its future lifespan is about 1041 cells. That is: It was implied in the...

I mean. For example, Earth in one month sweep the same area* than Jupiter in one month? *The line joining the Earth with the Sun than the line joining Jupiter with the Sun. I think yes, but is not what 2nd law says. I think in the fact that the aceleration just depends on the distance to the...

I'm new to this. I would like to know how we derive the earth's yearly mean temp. I assume there are thermometers all over...

when a star goes supernova, does it eject out earth, mercury and mars sized chunks. Surely the asteroids that are even the size of Texas won't have enough gravity to compact hard enough to become one chunk. What is the current belief on how large of chunks are ejected from a supernova. Thanks

In the first part, I'm asking about acceleration of freefalling objects with different masses. In the second part I'm asking about acceleration of one object with decreasing distance. Please explain where am I getting it wrong. Thank You!

Can anyone tell me if this would be correct? Would Earth not be seen flashing from space like a lighthouse to a distant planet when it reflects oceans and then DMS as the sons reflection per perspective travels across land then back to Ocean then back to land? I'm sure it probably says that...

Because it rotates around its axis, then it has a rotational kinetic energy. But when it orbits the Sun, then it has an another rotational energy too. Would it be ##E_\mathrm{rot} = \frac 12 (\frac 25 MR^2+ Md^2) {\omega}^2 ##, where ##d## is the distance between the Sun and the Earth. I...

Let’s dubiously assume that these 4D atoms would have the same radius as 3D atoms. Let’s further dubiously assume that a 4D HyperEarth has the same number of atoms as 3D Earth. Then the diameter of HyperEarth would be less than a kilometer. Four dimensional Earth is much more compact. Wouldn’t...

Inverse square law would reduce the gravity from the parts of Earth that are farthest from our feet. It'll also reduce the gravity from Earth's center by a lesser amount, but would that be lesser enough so the gravity 20 kilometers under our feet is stronger than the core's gravity or even the...

I don't understand the question. how am I supposed to find the magnitudes and directions of the velocity from the figure?

I think that the work is meant to be work done for instance in power stations. Or is it similar to work I do on a body when I lift it for example? But how can we then do that work on our Earth? I just need to understand the task, otherwise I want to solve it myself. The problem involves...

It didn't work and I don't know how to do it.

I would like a table of Earth mean temperatures going back as far as available. Where can I find that?

Dear forum please help me with the following understanding: There is (are) such equipment Earth ground testers (https://www.fluke.com/en/products/electrical-testi...) - it is used to measure grounded electrical systems or to measure. Such equipment is having multiple poles that are attached to...

So, not looking for anything over complicated. Just been picking up some special relativity. How meaningful is the notion of now here on Earth? Is special relativity worth even considering for day to day interactions with others?

Surface acceleration is proportional to density and radius of planet (as 2 powers of R cancel with the volume) g(moon)/g(earth) = density(moon)*radius(moon)/density (earth)*radius(earth) = (1/4)*density(moon)/density(earth)

Modeling the time evolution of the sun and earth orbiting each other using ##F = \frac{GMm}{r^2}## is straightforward. However, it appears that modeling the time evolution of the same 2 body system using general relativity seems to be a hard/intractable problem? There was in depth discussion by...

I'm reading the Feynman lectures chapter on "Curved Space", section 6-2. Say we're trying to figure out a way to measure average curvature on Earth. We know that 3d space is curved if Euclidean geometry rules don't work - e.g. the ratio of circumference and radius of a circle isn't ##2\pi##, or...

What’s the coldest spot on Earth? NASA has pinpointed it — and the nights are deadly https://www.yahoo.com/news/coldest-spot-earth-nasa-pinpointed-125903009.html

If the Big Bang happened 13.6 billion years ago how can the James Webb telescope now see galaxies 13.3 billion light years away? 13.3 billion years ago the universe was 0.3 billion years old. How large was the universe at that time? If physical mater traveled in all directions from the point...

365 rotations - 365 days 365 days - 31536000 s apart from that I do not know how to continue the question

The recent threads about relativity and the (ersatz) twin paradox got me flummoxed (again). I referenced a story (A World Out of Time) where the man character came back to an Earth that was 3 million years older than when he left. The reason is that he journeyed to the galactic centre and back...

If I understand it well, 10 s did really passed in the rocket, it is according to the observer on the Earth, but if the man in the rocket measured the time, he would measure 10 s. But when we say that the man in the rocket is in an inertial frame of reference as well, he can claim that because...

This is a topic that almost no one can actually explain from what I found on the internet. This answer https://physics.stackexchange.com/questions/74625/does-alternating-current-ac-require-a-complete-circuit/74999#74999 is the closest I found so far. The idea is how the grounded neutral...

If I place a mirror on the ground facing upward, what color will those who observe it from space see?

This is actually two questions. They are In which courses or field work is general relativity taught as method and not philosophy? At which altitudes does the oblate Earth approximation matter? At stealth bomber altitudes? Somewhere between Earth and Moon (in perhaps inertial gyroscope...

I'm looking for a database of binary stars within 10 PC of Earth, including information such as eccentricity of orbits, their distance from one another, etc. I'm hoping to find a list with this information, or just a collection of pages with this information. I've tried Simbad but I can't find...

I get step 1, in which due to electrostatic induction the top part of electroscope gets positively charged while the leaves of electroscope become negatively charged. Now if we Earth the positively charged end of electroscope as shown in step 2, then electrons must flow from Earth to...

How did you find PF?: Google Hello, I am new here. I am wondering, how is it possible for nearly 70% of the spherical Earth to be illuminated by the sun every July 8th? How can a sphere be illuminated beyond 50% with a single light source. How do we explain this?

Earlier this year PBS NOVA broadcast a documentary on measuring mountains. It covered Everest (Nepali: सगरमाथा, romanized: Sagarmāthā; Tibetan: Chomolungma ཇོ་མོ་གླང་མ) and K2. The history behind measuring mountains and the elevations of Earth's surface is fascinating. The old way involved...

I am attempting this homework exercise part b). I've modified my code but I get error overflow message. My goal is to modify my code so it returns kinetic and potential energy of Earth's orbit. I made a new f(z,t) and modified the rows 99 and 100 with dz[2]=-G*M*m/r, and dz[3]=0.5*m*y**2 but...