Earth Definition and 1000 Threads

I have read that airplane pilots can first perceive the curvature of the Earth's horizon at an altitude of about 35,000 ft. (The horizon would be 230 miles away.) Precisely, what is the shape they see? I don't think it's an arc of a circle because of the angle of observation. Is it part of an...

Mankind just lost it's most important battle in history, what would Earth look like in 1000 years? What would change?

Humanity exctincted and after XXX years Earth is populated by "new" humans. How long could it take if exctinction happened in 2130?

What is Earth resistance? What is the standard value of Earth resistance? Please help me with reference. Your co operation will be highly appriciated.

Hello, I'm interesting in Earth Moon evolution history. I understand it is very complex problem, and I can find many articles about that. But I would like to start from beginning and add real condition on my model step by step (I hope good way to do something). I would like to start with...

Hello, I think I quite understand what is happening with Earth and Moon. Losses of angular momentum due to tidal effects. But I would like to find some article or text where this is described mathematically. I guess using some lagrangian function or something like that and for example the...

i was wondering, instead of thinking the apple was pulled down by some force to Earth , why didn't he think that there was a force pushed the apple down from above? , imagine when you leave in that particular year when he was alive.

I'm helping to install an above ground pool. We leveled the ground. This left a 22" berm on the high side. We left an extra foot of space between the berm and the pool edge, but we're concerned it's going to eventually creep down hill and put pressure on the side of the pool. How big of an...

This may sound like a dumb question, but I have been curious about this for a while. What would happen if something cast a large and persistent shadow on the same part of earth? Say the shadow was the size of the umbra during a total solar eclipse. What would that do to the earth? I know the...

I noticed that the Co2 is actually decreasing in the Eon time. My guess is lush vegetations or forests began to grow which absorbed the Co2 by photosynthesis? Would anyone give me any clue?

Hello, This problem has probably been done before in different guises but I am struggling, and hoping for help. I am struggling to understand a phenomena which I am assuming is one and the same: Equatorial Bulge of the Earth Flat Plane in which the Planets rotate Protoplanetary disks are flat...

I have a doubts related to gravity How do this gravity come into existence? What is a cause of gravity? Why two masses are attracted due to gravity?

So, I heard the other day from someone online who claimed that if the sun would to suddenly disappear that the Earth would still travel in its regular path for 8 minutes before breaking off. The person claimed that because it takes light 8 minutes to reach Earth, and that since nothing can...

Homework Statement A spaceship leaves Earth at time ##t=0## with constant speed ##u##. Its clock is synchronized with the terrestrial one. At time T an earthling reads with an optical telescope the clock inside the spaceship. What value does he read? Homework Equations Lorentz equations. The...

Is solar uv completely blocked from reaching Earth or do we just need more sensitive uv detectors to make ground-based observations? In particular of the uv wavelengths corresponding to hydrogen Lyman series lines.

Homework Statement A rocket moving in space, far from all other objects, has a speed of 3.0 × 103 ms−1 relative to the Earth. Its engines are turned on, and fuel is ejected in a direction opposite to the rocket’s motion at a speed of 5.0 × 103 ms−1 relative to the rocket. What is the speed of...

So after watching this, circling around the Earth 7 times per second, close to the speed of light, one week of travel results in 100 years on Earth. Simplifying, 1 second on the machine versus 5200 seconds on earth. So I have to ask, how many times did the machine travel around the Earth ? 5200*7 ?

Homework Statement a comet is orbiting around the Sun in a parabolic orbit . center of the sun to perigee of the comet's orbit distance is 58 km . find the time required for the comet to transit into the Earth orbit around the sun . Homework Equations The Attempt at a Solution no clue

I am a student of science.I know that the compus works for magnetic field on earth.But I don't know the actual cause of this magnetic field.Compus always set in north and south direction. Sometime I thing ,Is there any magnetic hill on north or south poll?Or this is the cause of spin of the...

What is the value of curvature which caused by earth(geodetic effect) on space-time?

It is a classic physics problem to calculate how long it would take to fall through a hole that passes through the center of the Earth to the other side, assuming Earth is a sphere with uniform density. I also remember being posed a problem for if you were falling through a hole that passed not...

(b) (i) A satellite of mass 2520 kg is at a height of 1.39 × 107m above the surface of the Earth. Calculate the gravitational force of the Earth attracting the satellite. Give your answer to an appropriate number of significant figures. Worked out to be F = 2.45 x 103 The satellite in part...

As we all know The Earth has a magnetic field. Why the objects on the surface of the Earth do not get magnetized? It is possible to measure the magnetic field frequency of the Earth?

how fast do we have to go if Earth had no atmosphere? i'm wondering why don't they send a small, but extremely fast projectile in front of the rocket, which heats and expands the air in front which reduces most of the friction? (maybe like a railgun?) does that not reduce the cost? or am i...

A person on Earth signals with a laser beam at 6 minute intervals. Another person on a rocket moving away from Earth at 0.600c detects the signals. At what time intervals does the person on the rocket receive the signals from the Earth. The formula we use is: Δt=Δto/sqrt((1-u2/c2)) u = 0.600c...

As we know, If you put charge on conductor then all the charge reside on the surface of the conductor and charge inside the conductor is zero and electric field is also zero. Earth is also a good conductor. So the charge resides on the Earth surface? Is there no charge inside the earth? And...

It would seem to me that if you fly from point a to point b following the rotation of the earth, you'd have to go faster than this rotation to move forward. For example, if the Earth spins at 1,040/mph, then wouldn't a plane have to go faster than this just to escape the spin of the earth? I get...

Homework Statement The metric near Earth is ##ds^2 = -c^2 \left(1-\frac{2GM}{rc^2} \right)dt^2 + \left(1+\frac{2GM}{rc^2} \right)\left( dx^2+dy^2+dz^2\right)##. (a) Find all non-zero christoffel symbols for this metric. (b) Find satellite's period. (c) Why does ##R^i_{0j0} \simeq \partial_j...

Is there something in General Relativity whose value is 9.8 m/s2 at the surface of the Earth?

Homework Statement A satellite of the Earth has a mass of 1550 kg. It orbits Earth with a mean radius of orbit of 7.00 x 10^6 m. a) What is the gravitational potential energy of the satellite with respect to Earth? b) What is the kinetic energy and the velocity of the satellite in Earth’s...

I certainly hope that this is tossed out. But I've seen crazy things like some of the propositions in California. http://www.stuff.co.nz/world/americas/68342454/woman-sues-all-of-the-gay-people-on-earth

Homework Statement The mass of the Earth is 5.972 x 10^24 kg and its orbital radius is an average of 1.496 x 10^11 m. Calculate its linear momentum. Homework Equations P=mv The Attempt at a Solution I am not sure how to start? Given: mass= 5.972*10^24 kg Radius(to travel around sun)...

How do you know the shape (land altitude, roughness, etc.) of a specific location on Earth through a satellite? For example, if a specific place is covered by clouds is there a way to know the shape of the ground at this specific point? I have read through the absorption spectra of the...

During a physics lecture, the professor demonstrated how to find the period of an object that was dropped through a hole drilled straight from one end of our planet to the other. He finished by saying "an object orbiting the Earth near the surface will have a period of the same length as that of...

Let's say a spaceship made of a transparent material moving past the Earth in a straight line at a constant speed of 0.99 c, and it's at its minimum distance from Earth. If a light is turned on in the middle of the ship, for an observer on Earth will the light move towards the front of the ship...

How can I prove to my 9 year old daughter that the moon is closer to Earth than the sun? At the moment, she has read it in books and this information has the same status as unicorns and fairy princesses!

Homework Statement A body is suspended on a spring balance in a ship sailing along the equator with a speed ## v' ## . If ## \omega ## is the angular speed of the Earth and ## \omega_0 ## is the scale reading when the ship is at rest , the scale reading when the ship is sailing, will be very...

I moved to Australia from the US and took my Crate amp and Ibanez electric guitar with me. To deal with the 240 VAC, I needed a step-down transformer. So I have this setup: The ground connector of the socket on the 120 VAC side got weak and stopped making connection (Note 1). So the guitar...

There is only one planet (Earth)have life in the universe.But this is invented by human; the son of Earth! Is any other life live away from the solarsystem? I don’t know!…..oureyes&ears reach not so much. We are the most advanced biota among others in the earth. And we take oxygen as the life...

Homework Statement An airplane flies from the North Pole to the South Pole, following a winding trajectory. Place the center of the Earth at the origin of your coordinate system, and align the south-to-north axis of the Earth with your z axis. The pilot’s trajectory can then be described as...

I have heard that AntiMatter is the costliest material on Earth costing around $62 trillion per gram. How true is that and why? Who calculated this? What does antimatter do? Please shed some light. Thanks!

Homework Statement The flattening of the Earth is defined as f⊕ ≡ 1 - (Rp - Re) where Re is the radius of the equator and Rp is half of the distance between the North Pole and the South Pole. Estimate the flattening of the Earth. Homework Equations Fg = Gm1m2/r2 The Attempt at a Solution...

Homework Statement A satellite is in a circular equatorial orbit around the Earth (over the equator). If the satellite flies over Singapore 9 times a day, what is the radius of the orbit? Homework Equations r3 = T2GME/4π2 The Attempt at a Solution G = 6.67x10-11 ME = 5.97x1024 T =...

I had this though back in collage and asked my professor and he gave me a very short attempt to answer the question then said he was never quite sure about all this relativistic stuff... I didn't get my answer though but I have not forgot my question. Say a spaceship was headed toward the sun...

Does time go slower on the hemisphere of Earth that is currently rotating counter to Earth's orbit than the side the side that is rotating with Earth's orbit

Namaste If escape velocity on Earth is 11 km/s and velocity of Earth is 30 km/s how is that the atmosphere doesn't escape the pull of earth. Is the escape velocity with reference to Earth ? I don't think so because when finding the formula we add kinetic and potential energy and then equate to...

Homework Statement There is a system consists of a ball and the earth. Explain why you can consider the kinetic energy of the system equals to the kinetic energy of the ball. Homework Equations ##F=-\frac{m_{1}m_{2}}{{r}^{2}}## The Attempt at a Solution The magnitude of the force acting on...

I found this forum while searching for information on William Close Earth Harp. There is a closed thread here on the subject though it seems some are still in doubt one could tease sound from a long string device. While William created his Earth Harp in 1999, Ellen Fullman created her long...

In Principle, gravitational constant is measured very precise, but the problem is that it is measured together with mass of sun, Earth or moon, G M_s or G M_e; or G M_m. But, is it possible to measure mass of the moon without use of G? Maybe the principle, where the rocket was accelerated when...

I'm working on a potential sci-fi story that takes place on a post-apocalyptic Earth. The idea is Something Horrible 1A happens, then, 15-20 years later, Something Horrible 1B comes to finish us off. In a perfect world, the Moon is gone after 1A. Initial possibilities included a long orbit...