Earth Definition and 1000 Threads

For the sake of this challenge, you can assume that the world behaves nicely (everything is continuous, differentiable etc, the world is a sphere blah blah blah) but figurative bonus points if you assume fewer things. If you're looking for an easier challenge check out Challenge 10a. The...

For the sake of this challenge, you can assume that the world behaves nicely (everything is continuous, differentiable etc, the world is a sphere blah blah blah) but figurative bonus points if you assume fewer things. If you're looking for a bigger challenge check out Challenge 10b. The...

Hi, I'm sure this topic has come up before, however, it was always under the requirements of being realistic, i.e. taking drag, air resistance, Earth rotation and what not into account. Also, I couldn't find any equations so that I can do the math myself. Hence, here is my question...

I understand there are two factors: the gravitational forces from the sun and the moon and rotation. Rotation has a greater effect than the gravitational forces, so rotation is what I'd like to focus on. When the Earth spins, a centripetal force acts on the Earth's crust and points to the core...

Hello, everyone :-) We have a wooden sphere at a height of h = 1 m above the surface of the Earth which has a perimeter of RZ = 6 378 km and a weight of MZ = 5.97 · 10^24 kg. The sphere has a perimeter of r = 1 cm and is made of a wood which has the density of ρ = 550 kg·m − 3. Assume that...

Lets say Earth lost its magnetic field 4 billion years ago and lacked geological activity like mars. Would the atmosphere of Earth be comparable to Mars atmosphere? How thin could it have been without a magnetic field and constant geological activity? Thank you.

Hi everyone I had this very silly question pop up that unfortunately I cannot find an answer to myself. If an object - say, a hot-air balloon - flies at a low altitude above the Earth, it will of course remain above the same spot; you could I guess say that it rotates together with the Earth...

I have an enigmatic problem that I cannot explain. I have on video the results of this experiment at particular location where I believe bio-electromagnetic weapons testing is occurring. Does anyone have theories of why the following occurs? I have several sized physical compasses that...

Homework Statement a) What is the angular speed ω about the polar axis of a point on Earth's surface at latitude 40° N? (Earth rotates about that axis.) I solved this part b) What is the linear speed v of the point? Homework Equations v = ωr where r = radius of Earth at latitude 40°N The...

Homework Statement Consider the Earth's radius to be 6.40x103km, its mass to be 6.00x1024kg, the Moon's mass to be 7.36x1022kg, and the Moon's radius to be 1.74x103km. The average value for the Earth-Moon distance is 3.84x105kg. Neglect friction and rotation. a. Sketch the potential...

Homework Statement An Earth satellite has a speed of 29300 km/hr when it is at its perigee, 246 km above Earth's surface. Find the apogee distance, the speed at apogee, and the period of revolution. I thought I had this problem but I must be doing something silly because my answers are wrong...

Homework Statement On the Earth the Sun appears to rise and set about 365 times in one year. During the same 365 days, how many times does the Earth rotate on its axis relative to a distant star (a star beyond the Sun and out of our solar system)? Homework Equations The Attempt...

Homework Statement Determine the angular momentum of the Earth about its rotation axis (assume the Earth is a uniform sphere). Homework Equations L = Iω I = (2/5)Mr^2 ω = 2\pi/T The Attempt at a Solution I = (2/5)(6.0 X 10^24 kg)(6.4 X 10^6m)^2 ω = 1.992 X 10^-7 rad/sec L =...

If we let a thing from a height,earth force that with F=m*a=m*g=B(weight). BUT What is the power of earth,when the thing goes down(the power that force the thing at Earth too).I mean the different power,that keeps that in the ground. Logically the force of earth,is about the speed of thing,but...

Homework Statement A projectile of mass m is fired from the surface of the Earth at an angle α from the vertical, where α = 0.46 radians. The initial speed v0 is equal to √{GM/Rearth}. Calculate the maximum height that the projectile will reach. Neglect air resistance and the Earth's rotation...

Homework Statement A puck slides with speed v on a frictionless ice that is level in the sense that the surface is perpendicular to geff at all points. Show that the puck moves in a circle as viewed in the Earth's rotating frame. Determine the radius of the circle and the angular frequency of...

Homework Statement If we connect the neutral and Earth wires wrongly in the plug, can the appliance still work? Homework Equations The Attempt at a Solution I am not too sure, but my answer is probably no. The circuit cannot be completed, as the current will flow to the ground...

I am trying to figure out an equation that will allow me to calculate the mass lost of an asteroid that is coming towards earth. I know what I need to know the melting point of the asteroid, in this case we are using a completely spherical iron asteroid. Also kinetic energy would most likely be...

Calculate the 3 missing values from the system above assuming that it is in equilibrium i) Plant uptake = 196940 ii) Ocean deposition = iii) Weathering of calcium phosphate minerals = I can't seem to understand how you find the missing parts of the model image attached I know the...

Hello again :), I have to solve a rather extensive task. Most important are questions a) and c). I appreciate any help :)! Homework Statement The task: Determine characteristics of a Hohmann transfre towards, when circular planetary orbits around the Sun with R_E = 149.6 \cdot 10^6 km...

Or get so close that human life will be destroyed

Assuming no other compounds are initially present, what would happen to a body of Earth's mass, orbiting the sun at Earth's distance and speed, which is entirely composed of water? Assume that it just blinks into existence, and initially all the water molecules are arranged in a liquid sphere...

If an electron orbital the Earth only influence by gravity,does it emit electromagnetic waves? if so, the radius will decay,eventually falling on earth?

does direction of magnetic field influence the process occurring in brain? what are the other external factor that influence the brain other than information?

<< Moderator Note -- 2 threads merged >>

Homework Statement I have these equations: ga = exp(-σ^{R}Δt/ε_{0}*ε^{R}_{r}) Homework Equations σ^{R}=(ε_{0}*ω^{2}_{p}*v)/(ω^{2}+v^{2}) The Attempt at a Solution %ionospheric profile for earth-ionosphere waveguide as coefficients e = 1.602e-19; % electron charge...

I'd like to graph the function of and object falling to Earth from a point high enough that air density has an effect on the rate the object falls due to gravity. I'm not really sure where to start though. I'm thinking about that guy that jumped from the highest point ever free-falled from...

In a power station, the transformer's neutral wire is the same which is connected to earth. My question is if the neutral and the Earth is basically the same wire, can we use the Earth as our neutral point? i mean will it be a closed circuit where current will flow if we connect our neutral wire...

Homework Statement This is third and last part of a question whose first part was solved on here earlier. Given the spin angular momentum of the Earth and the Orbital (around Earth) angular momentum of the moon calculate the mass of an object that if it hit the Earth at it's radius (glancing...

Homework Statement Find the hill radius of Earth and calculate the velocity of an object falling from that radius (and from rest from the Earth's frame) at the point where it impacts the Earth. Relate this velocity to the escape velocity of Earth. Homework Equations Hill radius: r_h=R...

My physics buddy and I have been having a debate. I was claiming that even under the natural Earth's magnetic field that with good signal to noise ratio based on the radar systems scaled appropriately the top layers of the Earth could be seen. He claimed that the signal to noise ratio of the T1...

If so, how??

From what I understand, all life on Earth is descendent from a common ancestor, which was probably a self replicating molecule that spontaneously formed billions of years ago. As I think I understand it this single molecule self replicated, and succesive generations of the replicated molecules...

IN a relatively circular Earth orbit, how far away from Earth would you have to be in order to avoid collisions?

What would Earth be like with a 45 degree tilt?

Though this topic mentions climate change, I don't think it really is about it that, strongly anyway. I've just joined and noticed a ban on climate change discussions before posing this one, I don't think this is one, but if it is, I suppose the beast must have one of it's many heads chopped...

Hi! I have been told that despite the different temperature between the surface and the Earth is different we can't use it to produce electricity by using the laws of thermodynamics .. shy isn't possible ?

http://science.nasa.gov/science-news/science-at-nasa/2013/10sep_firestation/ In recent decades researchers have discovered some strange things happening in the cloud tops. High above ordinary lightning, exotic forms known as red sprites and blue elves shoot toward the heavens, cold cousins to...

Everybody knows that two object run together to the Earth despite of their mass. For example we have a object with 30 kg and one with 50 kg and let them from a big height. The reason that they will reach at same time will be that the Earth will put different power about their mass so to catch...

Homework Statement Eratosthenes measured the circumference of the Earth by noting that the Sun is at an angle of 7°12' = 7.2° ("one-fiftieth of a circle") south of the vertical in Alexandria at the same time of day and year that it is directly overhead in Syene. Syene is 5000 stades directly...

Is it likely that the Earth will survive or more likely that it will be engulfed?

I've recently read that an Earth sized planet that is a lava world orbit its star closer than Mercury orbits the Sun that was recently discovered. http://local.msn.com/new-planet-discovered-with-a-lava-ocean-and-an-8-hour-year

This is a neat site where you can explore various historical timelines. From the universe, to the Earth to even the ancient Greeks. The website is a little tricky to figure out, but once you do, it's quite powerful...

Hi my name is HopelesslyFaithful (HF) (forum didn't allow all chars). I am from Notebookreview and while googling for my project. I came across this site a thread that was helpful but also made more questions. I posted this on NBR so i did a direct copy paste hoping i could get some expert help...

How does Jupiter "protect" Earth from comets and such? I've commonly heard that Jupiter protects Earth by flinging comets out of an orbit that would otherwise leave them heading for Earth. I understand that Jupiter can throw comets and other objects out of their current orbit when they pass by...

I am wondering if a Super Earth planet with 2x Earths diameter and 8x Earths mass could have atmospheres below 10 bar? If so how could they be formed? Im asking because its theorized that super Earths will have thick hydrogen atmospheres. I was wondering if Super Earths could have thinner...

Show that the kinetic energy of the Earth after a collision can be ignored (stuck & desperately need help)? A ball of mass m2 is dropped and bounces off the floor. If the impact is viewed as an elastic collision between the ball and the earth, show that the kinetic energy of the Earth after the...

If a strong gravitational wave hit Earth would clocks record it? as if i understand it it is space time that is oscillating so the time component must be changing.

I want to find the ricci tensor and ricci scalar for the space-time curvature at the Earth surface. Ignoring the moon and the sun. I have used the scwharzschilds metric, but then the ricci tensor and the scalar where equal to zero.

Is there a Metric for the Sun and Earth other than the Schwarzschild Metric who has the Schwarzschild Radius on the interior of the body? What are the assumptions that turn that from GR to Newtonian? Rs(Earth)=8.87*10^-3m Rs(Sun)=2954m