Earth Definition and 1000 Threads

Hi all, i am trying to figure out if work done by gravity is positive or negative on an approaching meteor, I have used W(1->2) = integral (1->2) F(gravity) dot dr. and got a result of (GMem/r2) - (GMem/r1). Were G is gravity, Me is Earth mass, m is meteor mass and r1, r2 are initial and...

Assume the Hubble Space Telescope was in orbit around Pluto. What would it see when pointed toward Earth? I know the scene would change due to rotation and seasonal changes, but would our planet be blue? White? Green?

When people say that time measured from the Earth is equal to time measured from the Sun minus approx 8 min, are they taking into account Lorentz transformations or simply the fact that light takes approx 8 min from Sun to Earth?

This Science magazine News article discusses a new scenario for early Earth history that is claimed to explain the Earth's surface metal distribution and that it could effect conditions affecting the origin of life. This was before the end of the heavy late bombardment (timeline diagram in...

The Guardian - Adam Gabbatt @adamgabbatt Thu 10 Jan 2019 01.00 ESTLast modified on Thu 10 Jan 2019 11.02 EST A group of people who believe the Earth is flat have announced their “biggest, boldest, best adventure yet”: a Flat Earth cruise scheduled for 2020. Article continues...

Since I was very young I have wondered what life would be like if the Earth was a different shape. For example, what if Earth were two spheres stuck together rather than just a single sphere?Say the Earth consisted of two, same size, spheres connected at what is now our north pole with a...

Homework Statement Good evening, I have a homework where the question is "How high will person jump on Mars?" Homework Equations v2 = 2.amars.h1 V2 = 2.g.h2 The Attempt at a Solution I know everything to solve it. I can solve it by h1 / h2 . In this created equation the only unknown is h1...

A person of mass 60kg will weigh around 100N on the moon. This is roughly equivalent to the gravitational force on a 10kg object on Earth. Even if the forces acting on both are about the same, we don't see 10kg objects floating around on Earth whereas a man weighing 60kg can easily float on the...

Scenario: Large satellite arrays are at 90, 180, 270 degrees of Earth's orbit What is the fastest route to Earth 180? Possible fuels: liquid, solid, ion, sail, gravity The best route? Forward / backward ? Thrust when, from? Talk to me

I can find public information about the speed of the moon at max and min distance from the Earth (Ap vs Per) but how do I find the same information for the Earth's velocity around the same barycentre? The Earth's orbit around the barycentre is it a perfect circle or is it an ellipse? If it's an...

I where looking for elements that can absorpt neutrons without generating radioactive materials, and I found that most of them in Earth are suitable. I found that could work: C, O, Si, S, N, H The most common isotopes can receive one or two neutrons being stable, but if a neutron would be...

I'm reading Physics for Entertainment by Yakov Perelman and in it he says under "When we move around the sun faster" that at midnight the speed of the rotation of the Earth is added to that of Earth's translation effectively saying we move faster at night than during the day. He further goes on...

A recent Nat Geo article highlights a mysterious ringing of the Earth whose source is localized to the island of Mayotte but whose origin is unknown: https://www.nationalgeographic.com/science/2018/11/strange-earthquake-waves-rippled-around-world-earth-geology/ @davenn did you see this too?

I work for a company that locates underground cables and pipes. We apply an AC signal to the underground facility and to be able to detect the location. Take the simplified drawing above. Two transformers grounded with a buried electrical cable. We use a transmitter and connect it to one...

From Ars Technica: https://arstechnica.com/science/2018/11/why-does-flat-earth-belief-still-exist/

Homework Statement Somewhere between the Earth and the Moon there is a point where the gravitational potential due to the Earth exactly equals that due to the Moon. i)At what distance from the Earth is this point? Mass of Earth = 5.98x10^24 kg Mass of Moon= 7.35x10^22 kg Distance between...

Homework Statement Satellite orbits the Earth and its perigee r_min and tangential speed at perigee v_pe are given. The problem says do not use mass of Earth in the calculation, and use the only the constants g = 9.8 and radius of Earth 6380 km. I'm supposed to find the apogee and orbital...

it saids“if an apple is magnified to the size of the earth, then the atoms in the apple are approximately the size the size of the original apple” then why the atoms in the apple are "approximately" the size the size of the original apple, but not equal?

Do you have any own idea, on a way to protect the Earth from a possible asteroid impact? (You can not use technologies that are not invented yet, or imaginary. Those that can be invented in the next, let's say, 10 years, are allowed)

I was interested in whether it would be possible to move the Earth away from the Sun by using two ion drives on the Moon. One Ion drive on the far side of the Moon would operate briefly while the Moon was exactly between the Sun and the Earth. The other ion drive on the side facing the...

Heey everyone, I was wondering how long it takes for a small mass to reach the Earth from infinity . The trajectory is completely radial, so it's a relatively simple equation. $$r''(t ) =\frac{ - GM} {r(t)^2}. $$ But what if we multiplied both sides by ##2r'(t) ##. Then it follows, $$2r'(t)...

I understand quasars as black holes with an accretion disk and occassional jets of mass being shot out of the black hole from it's top and bottom. (Correct me if I'm wrong) If so, what is the actual possibility for that type of quasar to be rotated so heavily that it rotates on a horizontal...

Can someone explain the rare Earth hypothesis and the Gaian bottleneck hypothesis in detail. What are some thoughts on the Drake equation?

Hi everyone I've read that if Earth had no atmosphere it'd be completely frozen over with temperatures around 255K. Why is this the case when the moon has daytime temperatures of 373K (and night time temperatures of 100K)? Why wouldn't the oceans thaw during the day? Are they just too big...

Homework Statement Consider solar neutrinos of energy 1 MeV (EDIT: 10 MeV not 1 MeV) which are formed at the center of the sun in the ##\nu_2## eigenstate. What fraction of it do you expect to arrive at Earth as ##\nu_\mu## and what fraction as ##\nu_\tau##? Assume that it evolves adiabaticaly...

https://orig00.deviantart.net/1603/f/2018/163/d/8/great_lakes_earth_map_by_jdailey1991-dce7cbj.jpg Dark brown=mountains. Light brown=uplifts. Black=Igneous provinces still visible today at their original extent with no consideration of erosion. Let us say that, in the future, some scientists...

Hi there, I am making a very basic model of an earth, moon, sun system in ECEF in C# using the Helix Toolkit and in order to begin transformations according to Earth's rotation, tilt, and orbit, I need a reference orientation/position/time of Earth with respect to the sun and moon. So my...

Hello all! I am trying to make a VISUAL model (in C#) to predict lunar and Earth eclipse periods for a satellite that I have accurate ephemeris for. I want to calculate everything in ECEF reference frame. How would a go about modeling this system to the accuracy I'm interested in? I assume I...

I am currently working on a high power class E amplifier which will sit inside a metal enclosure. It is powered by two power supplies - both are isolated but one of the power supplies is mounted in the same enclosure. The power supply itself is in a metal case and that case is connected to...

This may be condensed matter physics topic, but I'm looking for a layperson answer. Scares of the CERN accelerator creating a black hole that swallows Earth are in the news once again. https://www.newsweek.com/earth-shrunk-tiny-hyperdense-sphere-particle-accelerators-1145940 From 10 years ago...

According to a survey in 2017, nearly half of the Americans believe, that aliens visit earth.However, I think that a lot of conditions have to be met, so that aliens would visit earth. First of all, they have to exist. Meaning their home planet has to be a habitable planet (but only a very...

What is the difference between man-made satellites and the moon that causes the former to drift towards the Earth but the latter drift away?

Scientists say when asteroids showered on Earth they were the ones who brought water to Earth which started life. But how did few molecules of water started life on earth?

I guess water in Earth , in big lakes or seas, looks blue because the Earth's sky is blue and the water's surface reflects the sky. Now if there would be some big lake of water at Mars, how the water surface colour would be? I guess the colour of Mar's sky which is red (right or wrong?) It is...

Hi All, What is the reason that makes the distance between the Earth and the Moon get larger and larger? Best wishes, DaTario

Imagine a person is moving at the equator in the direction opposite of the Earth's spin. How long would it take them to stop the rotation of the Earth? Assume: the person's "weight" = 90.718 kg, they person's speed = 1m/s, The Earth's "weight" = 5.972*10^24 kg, the angular velocity of the...

Because I must be a masochist I would like to know how I could convince a flat earther that the Earth is a sphere. The way I've chosen to do it is the following. I live in Honolulu and the person I am trying to convince lives in south america. At an agreed upon time we both take a 50 cm stick...

Homework Statement A new unit of length is chosen such that the speed of light in a vacuum is unity. What is the distance between the sun and the Earth in terms of the new unit, if light takes 8 mins and 20 sec to cover this distance? Homework Equations A new unit of length is chosen such...

https://amp.scroll.in/article/883720/how-we-proved-that-einsteins-theory-of-general-relativity-holds-true-even-beyond-the-solar-system Read the Section in this link: Cosmic alignment The galaxy we investigated has the catchy name ESO 325-G004 – let’s call it E325. Located some 450m light years...

What would be the value of gravity on the surface of the Earth if its mass was twice as large and its radius half of what it is now?

Homework Statement Find the period of a low Earth orbiting satellite using Kepler Laws earth radius = 6.38E6 meters T^2/R^3 for Earth = 2.97E-19 (sec^2/m^3) Homework Equations 2.97E-19 = T^2/(6.38E6)^3 T^2 = (2.97E-19)(6.38^6)^3 = 77.1 T = 8.72 sec The Attempt at a Solution This is not...

Homework Statement A) What is the weight (in Newtons) of an 80 kg person at the Earth's surface? B) What is the weight of the same person on the surface of the planet with a mass 8.0 x 10^24 kg and a radius of 5.5 x 10^6 m? (G=6.67 x 10^-11 N*m^2/kg^2) C) what is the apparent weight (scale...

what is the speed of Earth as it travels the cosmos,compared with the center of the universe.lets say the big bang starting point.?

I ask because time is defined with reference to this day (the SI second is based on a caesium clock is calibrated with reference to the 1952 ephemeris time standard, which was based on a second being 1/86 400th of Jan 0, 1900 (with Jan 0 being Dec 31 of 1899). So... how do I calculate the...

One day consists of slightly more than 360° of rotation (360.9856°) on it's axis (due to Earth's orbit around the Sun). I imagine that one orbit is also either > or < 360° around the sun, relative to the motion of the sun around some object. Is this true, or is the orbit of the Earth...

I saw the following question in Yahoo Answers, Is it even possible to know this?

I've been given a question to find the magnetic flux density of the Earth if an electron is orbiting near to the surface. The answer to the question makes the magnetic force equal to the centripetal force and solves for B from there. However, I am confused to why the gravitational force has no...

If alien were to establish a colony on earth, do they need human permission? ----------------------------------------- let's say they show up on sky where not belong to any country and create artificial island on international water to set up their own colony. even assume that they were...

Homework Statement How to determine GPE between moon and earth? Homework Equations mgh The Attempt at a Solution I know that gpe near Earth's surface is mgh, but at larger distances is there a specific way to calculate?