Earth Definition and 1000 Threads

Wikipedia states that: "If the measurement is close enough to the surface, light rays can curve downward at a rate equal to the mean curvature of the Earth's surface. In this case, the two effects of assumed curvature and refraction could cancel each other out and the Earth will appear flat in...

Dear All, Is it possible to watch Earth orbiting the sun in space like we watch a car coming towards us on a highway ? I mean, I would like to see it coming towards my spaceship at the rate of say 50 km/hr. Now some questions - 1. What should be my location and speed of my spacecraft...

Hello guys! I hope you can give me a hand with this one Homework Statement A satellite consisting of two masses attached by a rigid-massless rod of length L, are orbiting around the Earth at a distance R from the centre of the earth. During the entire movement the rod stays oriented in the...

I was wondering if there are any images of the Earth in 3D and flat, side projection that would show what the Earth looked like with all of the water removed and only the deep troughs and high plateau's remaining? The reason I ask is in reference to KIC 8462852. Would it be possible for a large...

Hey guys, take a look at this question if you may Suppose the moon, instead of a sphere, is a disc orbitating the Earth ( the moon's total mass is equal to the disc's total mass), the intern radius of the disc is equal to half the distnce between moon and Earth's center of mass and the external...

Hey guys! What would be the gravitational effect of Earth on it's surface, if somehow the density of mass was uniform and equal to 2/5 of the real value? Assuming that the size e shape os the planet doesn't change.

Hi guys! What would happen to objects on the Earth's surface if it SLOWLY stopped spinning and Earth's gravitational field was kept as always. Thx

Find the point between the sun and the Earth where the gravitational force on an object is equal to zero I know the mass of the sun is 1.989 x 10^30 kg G = 6.67 x 10^-11 The distance between the two is 1.49604618 x 10^11 The mass of the Earth is 5.962 * 10^24 I have the equation F =...

My name is Vamsi and I am from India. I am currently pursuing Ms in ME at University of Houston-Houston-Texas-USA. I have taken a course called "space vehicle design" in which we need to form a team and do a project of our choice. My team project is "Designing a space capsule to carry...

I'll start with this question, how much "mass" does something have to have before centrifugal force exceeds gravity on earth? I used basic physics of centrifugal force and gravity, used force vectors, and the math doesn't jive. This is what I mean. There are 2 forces on Earth that everything...

I know once the escape velocity is reached, the object will continuous to move away from the Earth. But the Earth's gravity can still act on the object no matter how far it goes, so what keeps the object from stopping or even returning back to Earth? Thanks in advance!

Homework Statement Name a strength and weakness of each technique. Homework EquationsThe Attempt at a Solution The two techniques that I came up with are: Magnetic Line of Force in rocks to analyze land-based paleomagnetic data. Strength: Well, it's easy to collect. [need help here]...

http://www.natureworldreport.com/2015/10/a-piece-of-space-junk-wt1190f-will-impact-earth-on-november-13/ On November 13 a small chunk of junk, named WT1190f will crash into earth; origin seems to be unknown. No , not aliens. It is human-created space junk. Does anyone know more about the...

I know that the angular momentum of the moon with respect to the Earth can be calculated by L = Iw but if the L of the moon is k * Learth-sun the there will be way more eclipses, one of each every 28 days. So the momentum of the moon must change over time, how does it work?

Hi, folks. There's a somewhat popular hypothetical situation that involves a person falling into a hole dugg all the way through the Earth or any planet, passing straight to its center. Now, I understand quite well that the resulting motion would be periodical and the reasoning behind it. My...

Muons time dilation from the Earth's frame (and length contraction of Earth's atmosphere from muon's frame) is the usual explanation of the fact that muons reach the Earth when they shouldn't just by their rest half-life. My question is if the explanation based on differential aging(different...

http://www.sciencedaily.com/releases/2015/10/151006192107.htm A new study shows that iron-bearing rocks that formed at the ocean floor 3.2 billion years ago carry unmistakable evidence of oxygen. The only logical source for that oxygen is the earliest known example of photosynthesis by living...

Someone texted me and asked me if the Earth was half as massive what impact would that have on the rotation period of the moon? I'd think that the moon would rotate slower as it's gravity would more influence on the earth. But I am not sure if that makes sense or not haha

Homework Statement At a latitude of 50° north a mass is hanged by a massless string. By the means of an angle how much does the mass deviate from the Earth's radius due to rotation of the earth? Consider the Earth as a spherical body. Homework Equations Fcp=mv^2/r w=dθ/dt v=wr The Attempt at a...

Hello Forum, When we take a small metal sphere of radius R1 an charge Q1= 1C and a larger metal sphere with R2=20*R1 and charge Q2=-2C. The spheres are initially separated. Being conductors, all the charge resides on the surface of the spheres. Sphere 1 has an electric potential V_1 (relative...

Tltr: The quesion d makes no sense to me and I don't know what my teacher mean. 1. Homework Statement The Earth turns once around its axis in 24.0 hours. We will assume that it is perfectly spherical, with radius 6400 km. The mass of the Earth is taken to be 6.00 × 1024 kg. The gravitational...

we cannot find Earth speed..,.,.,.,,. to find speed of an object we want a stable surface. lets go through an example:- if a train in moving with a speed of 100 km/hr and a car is in top of the train moving with a speed of 50 km/hr (in same direction). then the speed...

I've run into a couple of problems with exercise 12.6 in MTW (attached). At this stage, all I'm asking is for someone to give me answers to the following questions: 1. What are the Rα'β'γ'δ' in the primed co-ordinate system? and 2. What are the non-zero connection coefficients in the...

if we fix huge amount of mirrors on surfface of moon...can we obtain light on Earth during night ?

Assumption: Earth is a perfect blackbody. This means that the emissivity (ε) is 1. Earth’s radius = 6371 km Incident solar radiation = 1367 W/m2 Temperature in space = 0 K I'm given the above data. I tried using the E= σεTe4 but that doesn't include the radius of the Earth :S Im really...

I have a circle, representing Earth with equator drawn on it. I need to draw longitudinal lines on 15 degree, 30 degree, and 60 degrees distance? I am not sure how and from where to measure these angular distances. Thanks.

Problem: In analogy to the Bohr Theory of the hydrogen atom, develop a quantum theory of Earth satellites, obtaining expressions for the orbit radius (r) and the energy (E) in terms of the quantum number (n) and the other relevant parameters. A satellite of mass 1000 kg is in a circular orbit of...

When I connected the positive terminal of the battery to one terminal of the bulb and the other terminal (of the bulb)to the ground the bulb did not glow, even when a potential difference exists?

Homework Statement When a ball is bounced from the ground, the Earth exerts the force necessary to reverse its velocity. Is there a simultaneous force exerted on the earth? If there is one, why don't we perceive any acceleration of the earth? Homework Equations Newton's second law: net F=ma, F...

Why does the Earth not fall into the sun? Is it because Earth has angular momentum? or is it because the Earth has orbital momentum?

Take some high voltage power line. Place a conductor between the wire and Earth ground. Current goes to ground. Why? I understand what is voltage, resistor, circuit etc. I do know that the wire is at a higher voltage than the ground. But isn't Earth also a kind of huge resistor? Thus preventing...

Is there a way to determine the arc around 1/4 of the Earth without measuring it? I mean like thru trig?

Here is a review article identifying some causes for the high temperature in the central volume of the Earth. http://www.scientificamerican.com/article/why-is-the-Earth's-core-so/ Inside all massive astronomical bodies like the Earth, collisions of atoms occur in a gravitational field. Because...

Hi, I'm trying to figure out how big an asteroid we might be able to "capture" and bring back into Earth orbit for mining - both with today's technology and with potential technologies of the future. Specifically I am looking at a rock that is 500 feet in diameter and relatively round. My math...

Homework Statement Light from the sun reaches Earth in 8.3 min. How far is the Earth from the sun? The velocity of light is 3 × 10^8 m/s. Answer in units of m. Homework EquationsThe Attempt at a Solution 8.3 min = 498 sec 3e8 x 498 = 1.494e11 m

Dear PF Forum, Does the Earth core produces its own energy? If it is true, how? Radioactive decay? Gravity? Earth core temperature is around 4000 Celcius. Almost like the sun surface temperature. How can that temperature kept for 4 billions of year? Can the temperature heat the mantle and Earth...

When conductor is connected to earth..all the charges are shown to be flown to Earth in textbook hc verma...But i found in its examples the charges are however not zero on conductor when it is connected to earth.. If it charge is not zero on connecting to Earth how will the capacitor work...?

i knew during geology survey, they can drill into Earth thousands of meters below the surface. just curious how did they accomplish that?

Consider that Earth was placed freely in space, away from the sun. Then another, but similar Earth is brought carefully in contact with it, so that the two planets get locked in place by their mutual gravity fields. Now, would the Earth's suffer a structural collapse, or would they remain more...

would that person go into the future?why? also if i travel 1,000,000 m/s on Earth and my friend travels 20m/s per second on Earth would we experience 2 different time frame? so basically the second question is if someone travels a different speed than me on Earth whether the difference of speed...

Say hello to HD 219134b - a rocky exoplanet recently discovered using HARPS-North instrument on the Italian 3.6-meter Galileo National Telescope in the Canary Islands, who's existence has been confirmed by NASA's Sptizer Space Telescope. At a distance of 21 light years, it is the closest...

Hi guys, I am new to the forum and I have what is probably a simple question for most of you. Unfortunately a great deal of people I know have suddenly taken up the idea of a "Flat Earth", and they consistently post things that try to contest that a flat Earth is a far more logical idea than a...

Hi all It's a well known fact that the moon is drawing away from Earth by 3.82 ± 0.07 cm/year. I was googling a lot to find the exact distance between Earth - moon that this data was measured. A plain number or a link will be much appreciated. Thanks in advance Elistein

Can we use fast-growing sea plant to increase the surface area of the sea, enhance global evaporation, and get the Earth cooler? Do we know some sea plants growing really fast with photosynthesis? I was struck with this idea when I was doing a search on giant vegetables on land.

Homework Statement The distance between the centres’ of the Earth and Moon is estimated to be 3.84x10^8 m. If the lunar month is 27.3 days, calculate the approximate mass of the Earth. (Assume the gravitational constant G=6.67x10^-11 Nm2 kg-2) Homework Equations [/B] T = 2pi / sqroot(G *...

If the Earth were to vanish. Like the thought experiment that posits the sun suddenly disappearing to explain the 8 minute delay in the effect on the Earth, so I posit the Earth from the surface down vanishing in equally metaphysical and mysterious circumstances in order to help me to see what...

DaleSpam submitted a new PF Insights post Understanding the General Relativity View of Gravity on Earth Continue reading the Original PF Insights Post.

I'm reading through Sparknotes' explanation of the equation: U = -Gm1m2/r "Off the surface of the Earth, there’s no obvious reference point from which to measure gravitational potential energy. Conventionally, we say that an object that is an infinite distance away from the Earth has zero...

I'm trying to find a correct circuit diagram for how a floating Earth is correctly wired for a small generator that is not being bonded to ground using an Earth spike. It may be that there's more than one legitimate way which is why I'm confused, but even manufacturer diagrams are contradictory...

Most presice measurement to date done by MINOS of neutrino time of flight through Earth published two days ago, once again found neutrinos slightly faster than light speed within statistical errors. Only when they extend the band with systematic errors doesn't neutrinos surpass light speed...