Earth Definition and 1000 Threads

I have some puzzles when I combine the Equivalence principle and Unruh's effect. Equivalence principle says that acceleration is equivalent to a uniformly gravitational field, or locally equivalent to gravitational field. Then the electron sitting on Earth should have Unruh's effect, i.e...

Homework Statement Homework Equations f = ma m1 = mass of moon m2 = mass of earth The Attempt at a Solution Ok this is crunch time here and i am NOT Kobe Bryant I have chosen gravitation between the moon and Earth for this project. I will start with the net force on the moon as ∑FSystem =...

Information Given:In 1956, Frank Lloyd Wright proposed the construction of a mile-high building in Chicago. Suppose the building had been constructed. Question: Ignoring Earth's rotation, find the change in your weight if you were to ride an elevator from the street level, where you weigh 708...

Hey guys! Can anyone tell me how to calculate the force of air friction on meteor that's going to impact

Hi! I'm playing around with an idea for a story set on an orbiter around Mars. While Mars and Earth were on opposite sides of the sun, Earth got hit by a colossal coronal mass ejection even bigger than the Carrington event of 1859. So they see Earth rise but can't pick up any radio signals...

Someone is asking me how much current in a loop of wire the diameter of the Earth to make the same level of magnetism the Earth has? I hope I am asking this correctly. TIA Clark

This is rather disturbing. https://weather.com/science/space/news/2018-04-17-asteroid-massive-2018-ge3-nasa-flyby

If/when we go to Mars how will we deal with time dilation due to the gravitational differences between the two planets?

Homework Statement Gravitational force exerted on mass m is GMm/r^2 2. Relevant equations Orbital velocity at distance R from Earth = ##\sqrt gR## Escape velocity = ##\sqrt 2gR## gR = GM/R Fc = mV^2/R F =m.aThe Attempt at a Solution 1) express acceleration of gravity in terms of G, M , and R...

Hello, I'm new at the forum. I'm a science-fiction writer. My question then concerns an imaginary, fictional situation. I'll try to be brief but it's not easy to explain: Let's imagine that a character who lives on Earth is strongly attracted by the gravitational force of some other celestial...

I've been trying to understand why we see different milky way arms depending on where we are on Earth and what time of year it is. I've been googling and I can't find an answer. Can anyone explain this to me? If you have a picture handy that would really help. Thanks.

A rocky Earth like exoplanet drifts into our solar system and will collide with Earth. It is 3 times the mass and diameter of Earth. We build a spacecraft to drill into the core of the Earth prior to the impact. Assume our craft can withstand 'infinite' pressure and temperature and is...

As I understand it Cosmic rays are mostly protons which have a positive charge. If the overall charge state of the Earth remans neutral is there a similar outflow of positive charge or a source of incoming negative charge? Google wasn't very helpful.

Struggling a bit in my astronomy class. Trying to understand ..Is there a way to make a 90 degree angle between Earth, Mars, and the Sun? Mars would be the vertex. Is there a simple basic answer? TIA

of God? Before you pounce, I'm atheist. And it's a legit theory: https://en.m.wikipedia.org/wiki/Gaia_hypothesis Could it be, that Earth and our other fellow Planets etc are these cells of God that rotate around his brain, the Sun, which is so full and bursting with knowledge that it scorches...

Im wondering what the night sky would look like if you stood on the surface of the Earth as it was forming? Here is my best guess, I would like to know if I am on the right track 1. After it cooled down, it had no atmosphere so it would be like the surface of the moon so the stars wouldn't...

Hi everyone, I work at a small high school that does one-on-one teaching with students who often have some kind of attention related learning difficulty or have trouble in a large classroom. The physics and chemistry courses I have been teaching have very inadequate lab sections and we have very...

(i.e the height you need to be at to look forward) (This isn't in physics subforum because it's more of a geometry question, this is NOT a homework question and it's more of a random thought) Basically, I've been thinking what height would you have to be at, to see 1° of Earth's curvature. So...

Homework Statement We release m_o = 1 kg object from h=1m height. How much does the Earth move (x)? I just need the comfirmation if I did correctly? Homework Equations Conservation of momentum: m_o v_o + m_E v_E = 0 The Attempt at a Solution I wrote the energy conservation law as (beginning...

Homework Statement Distance Earth-Sun at perihelion = 1.471×108 km Distance Earth-Sun at aphelion = 1.521×108 km Sun mass = 2.0×1030 kg Earth mass = 5.972×1024 kg G = 6.67×10-11 m3/kg⋅s What is the change in Newton of the attraction force between the Sun and the Earth from the perihelion to the...

According to various sources, the Moon is separating from Earth 4 cm every year. I’ve searched for the explanation and I’ve found the following: The friction the seas and oceans from the Earth make with it’s soil causes the Earth’s rotation to slow down. This causes the Moon to speed up...

well, we say that an object on Earth has a potential energy that is dependent on its position, i.e height. In this case we take Earth as reference point, similarly if we take sun as reference point, the Earth should have some sort of potential energy.

Im a bit of a physics newb so bare with me. I am designing a product that uses rare Earth magnets as a mounting solution for radar detectors and wanted to know if these magnets would somehow interfere with the performance of the radar detector? The magnets will not be mounted to the detector...

<<<Moderator's Note This thread was split form https://www.physicsforums.com/threads/are-the-terminals-of-a-battery-neutral.939947/>> because the grounding posts are interesting but off-topic to that other thread.>> The entire Earth (ground) might be charged plus or minus one million volts...

Is it astronomically known what the closest distance is between Earth and a black hole? (I was not able to locate an answer to this question searching the Internet.) If not, the article https://www.sciencenews.org/article/we-share-milky-way-100-million-black-holes says The Milky Way teems...

Homework Statement 14.100 Calculate the maximum and minimum distances in kilometres between the centers of the Earth and moon, taking the eccentricity of the moon's orbit into account. Use the data given in Prob. 14.99 Homework EquationsThe Attempt at a Solution Can you check my solution...

Homework Statement 14.99 Assuming that the orbit of the moon around the Earth is a circle (its eccentricity is actually 0.055), and knowing that the period of the orbit is 27.3 days, compute the distance in kilometres between the centers of the Earth and moon. Homework EquationsThe Attempt at...

Has the spectrum of light that is reflected off planet Earth ever been measured from outer space? (In the same sense that we measure spectra of the light emitted/reflected from other celestial bodies in astronomy). If so, would it be possible that there could be dips in the spectrum resulting...

What will happen if the center of mass of Earth was displaced for some distance away from its origin? Will that affect the Earth's rotation around itself or even around the Sun?

I know that energy increases with distance, but what is the relationship? What are different ways to measure something decreasing over distance or time. I really don't have the time to help my younger sister do her homework so I need someone to help me explain to her the relationship concerning...

We can indirectly measure the atmospheric composition of worlds outside our solar system. Suppose there are aliens out there. On their world, they use the same technique we use to measure the atmospheric composition of worlds. Suppose they turn their telescope on Earth. Is it possible they...

So recently I asked a question about a model of gravity I saw. Turns out I was misinterpretating it, it was the wronv source to use. Here is a video by PBS ( ) talking about what I was trying to say, that is that some people say 'The Earth rises to catch an apple, not vice versa. But, it...

I was thinking about this question: So if a rock fell 20,000 meters to Earth assuming no air resistance and no other gravitational forces from anything but Earth, how long would it take the rock to hit Earth? Keep in mind acceleration is changing through the gravity equation as the rock gets...

Has anybody attempted simulating the trip to the moon described by Jules Verne? I've done a bit of research and found this two posts: https://www.physicsforums.com/threads/showing-deadly-acceleration.909104/#post-5726115...

So i was just wondering if a satellite's circuitry could be affected by the Earth's own magnetic field inducing a current, if it was moving through it quickly enough (the space station for example), and how it might mess with it? Also considering a satellite is a big hunk of metal, could passing...

https://www.sciencedaily.com/releases/2018/01/180109112437.htm The Hypatia Stone is a small meteorite from SW Egypt. Petrographic and chemical analysis by a group of researchers mostly from University of Johannesburg found element abundances and other unique chemical anomalies in the meteorite...

So, from my last thread “Why doesn’t the water fall out of the Earth?” I asked if the reason why water doesn’t fall out of the Earth even on its tilted axis. Then the conclusion was gravity. To be more precise, gravity is the one that pulled the water on Earth into a ball form. What in gravity...

The discussion here https://www.physicsforums.com/threads/general-relativity-the-sun-revolves-around-the-earth.245334/ concludes that in general relativity there are no privileged reference frames so that, for example, it would be valid to use the Earth as a reference frame and say that...

While lying in front of a 500 degree woodfire, I wonder if besides light and heat that we take as ordinary does it also have ultraviolet rays of light like the sun?? What are the types from light from an ordinary on Earth fire?? Would they be beneficial to plants as main light source?, would...

I asked myself this question today, found that exact question asked here (February 10, 2005)... and I could not say anything, not even a squeak. Well, boil that dustmote! "Why would aliens come here?" I ask and the voices in my head speak. We are far from the galactic center of an average...

Problem - we have to use large amounts of fuel/propellant to exit the Earth's atmosphere to enter Earth orbit, the moon or other planets... Solution - would it not make sense to launch from a base on the moon? Problems I see, potentially... 1) Is the moon’s orbit around Earth problematic for...

Is there a programmable telescope that will point to any spot on Earth from my location that I could simply plug in the latitude and longitude and it would point at the location anywhere on Earth. For instance, if I wanted it to point at the LHC (Large Hadron Collider), could I just plug in the...

What particles(s) can pass through hundreds of miles of the Earth? Is it only neutrinos, or is there some other particle(s)?

Science news reports: (original report abstract here) Eleven micro-fossils though to be the remains of bacteria (some dispute this) from Australia dated to 3.5 billion years ago have been analyzed with secondary ion mass spectrometry (SIMS). This has revealed different ratios of different...

Don't we, as people on Earth, react to Earth the same way as paperclips are attracted to magnets? Why is "gravity" not magnetism?

How much energy needs to be be expended to throw a non operating satellite (or other space trash) out of orbit (L4 or L5) or L2 into deeper space... thus minimizing space debris in Earth orbit. I could only find formulas for getting an object INTO orbit... Background of question: we were...

Hi All, An observer, F, stands on Earth. A spaceship, F', is also on Earth. Their clocks are set at 0. The spaceship then leaves Earth at .5c. After 10 seconds, F sends a light signal to F'. As soon as F' receives the signal, F' sends a light signal back. When does F receive this signal from...

Homework Statement Homework EquationsThe Attempt at a Solution [/B] The thing to remember is that inside the Earth surface, the gravitational field does not remain inversely proportional to ##r^2##. The equation of motion is ## \ddot r = \frac { -gr} R## ....(1) This means that the...

Hi, I'm actually a teacher presently undergoing gravitation and circular motion with my students, and ran into a problem I forgot how to think through. I'm trying to explain Newton's cannonball thought process (shoot a cannonball fast enough off a mountain and it will circle the earth), and...

we know that the moon is far away the distance between us and the moon can fit all the other 7 planets and some small dwarf planets but how ? it would take us 3 days to reach the moon and the spacecraft were traveling in at least 240,000 miles it should take us more than a year to reach the...