Earth is the third planet from the Sun and the only astronomical object known to harbor and support life. About 29.2% of Earth's surface is land consisting of continents and islands. The remaining 70.8% is covered with water, mostly by oceans, seas, gulfs, and other salt-water bodies, but also by lakes, rivers, and other freshwater, which together constitute the hydrosphere. Much of Earth's polar regions are covered in ice. Earth's outer layer is divided into several rigid tectonic plates that migrate across the surface over many millions of years, while its interior remains active with a solid iron inner core, a liquid outer core that generates Earth's magnetic field, and a convective mantle that drives plate tectonics.
Earth's atmosphere consists mostly of nitrogen and oxygen. More solar energy is received by tropical regions than polar regions and is redistributed by atmospheric and ocean circulation. Greenhouse gases also play an important role in regulating the surface temperature. A region's climate is not only determined by latitude, but also by elevation and proximity to moderating oceans, among other factors. Severe weather, such as tropical cyclones, thunderstorms, and heatwaves, occurs in most areas and greatly impacts life.
Earth's gravity interacts with other objects in space, especially the Moon, which is Earth's only natural satellite. Earth orbits around the Sun in about 365.25 days. Earth's axis of rotation is tilted with respect to its orbital plane, producing seasons on Earth. The gravitational interaction between Earth and the Moon causes tides, stabilizes Earth's orientation on its axis, and gradually slows its rotation. Earth is the densest planet in the Solar System and the largest and most massive of the four rocky planets.
According to radiometric dating estimation and other evidence, Earth formed over 4.5 billion years ago. Within the first billion years of Earth's history, life appeared in the oceans and began to affect Earth's atmosphere and surface, leading to the proliferation of anaerobic and, later, aerobic organisms. Some geological evidence indicates that life may have arisen as early as 4.1 billion years ago. Since then, the combination of Earth's distance from the Sun, physical properties, and geological history have allowed life to evolve and thrive. In the history of life on Earth, biodiversity has gone through long periods of expansion, occasionally punctuated by mass extinctions. Over 99% of all species that ever lived on Earth are extinct. Almost 8 billion humans live on Earth and depend on its biosphere and natural resources for their survival. Humans increasingly impact Earth's surface, hydrology, atmospheric processes, and other life.
is it because lunar eclipse shows that sun is bigger than Earth and moon, and solar eclipse shows that sun is too far because moon's shadow on Earth is almost a point.
Hi, Newton's 2nd Law states that when a net force acts on a body, it causes acceleration in the body...This is well for forces acting on bodies in space...But what about on Earth??...On Earth when you apply force to an object, the air around it pushes back with same force!, So where is the...
since magnetic field lines form closed loops , field inside Earth must be due geographic south
will compass below Earth's surface point to geographic south?
Why Is It That An Apple Will Fall On The Earth And Not That The Earth Will Live It Position And Move To Strike The Apple.is it just because that Earth has gravity. and Earth is a huge place very big material?
I've been doing some work with my classes around the Yuri Milner Breakthrough Starshot project to send a tiny nano craft of mass around a few grams to alpha centauri. The starchip would travel at 20% of the speed of light. I've had them calculating various properties of the ship including...
The other day I was wondering if as the universe is infinite and you can say that every single point in it is the centre of the universe, or that there is no centre for the same matter. Since you are not able to set up a centre in Earth's surface. Is then Earth's surface infinite?
When you talk...
Hello people,
I got a question and please do not understand it as a fake question.
In theory would it be possible that when it would come to a collision between the Earth and a big sized asteroid, huge jet engines placed on different places on Earth could bring Earth out of orbit and then...
On June 30, 1908, the remote Siberian region of Tunguska made headline news when an explosion knocked down 80 million trees in an area of only 770 square miles. The mystery was that there was no crater, which led to the assumption that the space bomb responsible for the catastrophe detonated in...
Homework Statement
A student runs an experiment with two carts on a low-friction track. As measured in the Earth reference frame, cart 1 (m = 0.48 kg ) moves from left to right at 1.0 m/s as the student walks along next to it at the same velocity. Let the +x direction be to the right.
A. What...
Homework Statement
(sorry for spelling of Earth, had to be to be done to fit it in lol)
Does a satellite in orbit around the Earth speed up as it falls towards Earth?
I understand why the satellite speeds up mathematically. If we equate the centripetal force equation and the equation for...
As I understand it muons have a half life of 2.2 microseconds, thus, at the speed of light cannot get to the earth. But based on exponential decay, of every billion muons which head or way, about 70 will actually get here. Using time dilation the full billion will get here.
Do we need a billion...
Meaning "would a planet the size of Earth with two moons the size of Luna be a stable system?"
I'm thinking of system where the moons are inhabited and the mother planet has been devastated by an asteroid impact. Naturally, they get to fighting (humans, what can you do with them?)
I have been studying astronomy and astrophysics for about 2 years now, though on my own time and by my self. A recent question came into my mind, Can arctic planets exist close to their star? Now, in my understanding of planetary science, in order for a planet to be cool and close to the sun, it...
Continuing a conversation from Electrical Engineering, here are a few links to discuss.
http://web.mit.edu/12.000/www/m2016/finalwebsite/solutions/asteroids.html
http://www.nss.org/settlement/asteroids/sonter.html
http://www.space.com/15405-asteroid-mining-feasibility-study.html...
Hi guys, I've recently been reading a lot of Jules Verne and I had a few curiosities that you guys could help with.
First, if we were to shoot or fling a bullet to low Earth orbit, what would the muzzle velocity have to be??
Second, instead of a bullet, if we used a capsule with one passenger...
From the observation point of Earth, you can say that the sky "moves" while the Earth is still. From this point, an observer on Earth would see a distant galaxy travel a circumference millions of light years lomg around the Earth in only a day - resulting in a velocity faster than light. Special...
When the the Earth is between the Sun and Moon do the gravitational effects of the Earth and Sun combine to create a stronger pull on the Moon? If so, wouldn't this increased pull draw the Moon closer and closer to the Earth over time? I've looked for an answer to this, but haven't had any luck...
Homework Statement
Homework Equations
Force due to gravity ##\frac{GM_em}{r^2}##
The Attempt at a Solution
C) is incorrect as there would be no torque on the satellite about the center of Earth .
I think B) is correct . But I am not entirely sure about the reasoning .Here is what I think...
Homework Statement
A rocket starts at rest from the Earth, moving in the z direction so that in its own instantaneous rest frame the acceleration is always g = 9.8 m/s^2. To an observer on Earth, its position is given by
## z(\tau) = \frac{cosh(g\tau) - 1}{g} ##
## t = \frac{sinh(g\tau)}{g} ##...
The Earth has a net negative charge whilst the Ionosphere has a net positive charge, this has been known for well over a hundred years now.
My question is about the negative charge of the Earth, are the free electrons on the Earth's surface stationary? are they whizzing around in the Earth in...
I'm trying to get an understanding of the Coriolis effect, and I understand it when the wind moves longitudinally (North-South). Basically, the wind has a certain horizontal component of its velocity due to the rotation of the Earth, and as it moves North or South the rotation of the Earth...
Q: Fred is on Earth, and Jane is on the Moon.
a) Each lifts a 2.0 kg rock. Who has to apply the larger force?
b) Each throws the rock horizontally with initial speed of 6.0 metres per second. Who applies the larger force?
For both questions, I wrote: Fred, because the gravity on Earth is...
1. In above image an insulated metal plate has been placed inside Earth (soil), and an voltage is applied between plate and Earth groung what will be the capacitance here??
2. one plate is the metal and the other plate is entire earth, so it is a big assymetrical Capacitor or What?
all...
Homework Statement
Sputnik I was launched into orbit around Earth in 1957. It had a perigee (the closest approach to
Earth, measured from Earth's center) of 6.81 × 106 m and an apogee (the furthest point from
Earth's center) of 7.53 × 106 m. What was its speed when it was at its perigee? The...
I'm trying to get my head around GR. As I understand it, any frame of reference is as valid as any other for modeling the universe. Therefore, it is valid to use a non-rotating Earth as a frame of reference, and try to model the movement that is seen from this frame.
But if that is true, I...
I have been reading about Mars and planetary rotation and gravity. It seems to me Mars was in Earth's rotation at one time. Most likely it's first period. I want it back. I don't believe it's an impossible task. People exercise drilling and fracking and sending out satalites. How impossible is...
Centrifugal force due to rotation of the Earth has among its effects the deviation towards the equator of a ball falling from height ##h## vertically on Earth.
I do not understand what is the inertial explanation of this phenomenon. Once the ball is released there is no centripetal force that...
I believe the first life to appear on Earth appeared in the oceans of Earth. When I ask if life would have appeared on Earth without oxygen, I am asking if life would have appeared in the oceans of Earth or on land without oxygen.
Would life have appeared on Earth without oxygen?
I remember a teacher said that the Sun is approx. only in its mid way of life and so there are still billions of years to go. I am not worried.
From wild guess, I am pretty sure our Earth will be finished well earlier before that of the Sun.
We are talking about global warming, water levels...
As far as I know, the Earth orbits around the Sun because of the centripetal force
, and as far as I know, friction and gravitation from other planets should affect the circular motion of the Earth and so the path of the Earth should not be necessary that perfect.
In addition, there must be...
I don't understand what are the causes of the Coriolis effect for objects moving with respect to Earth. For istance consider an object free falling on the Earth from an height h. Its tangential velocity its greater than the velocity of an object on the surface of Earth, hence it moves eastward...
I have learned that the gravity at the center of the Earth is zero. I guess its because it gets balanced as the force from all the sides are equal in magnitude and opp in direction. But several land forms throughout the world having different masses could cause a distortion which could make an...
Hi,
I was given the following question:
Show that Bose condensation does not occur in 2D. Hint: The integral you will get when you write the formula for N is doable in elementary functions. You should find that that N ∝ ln(1 − e βµ).
I do indeed find that N ∝ ln(1/(1 − e βµ)) ∝ ln(1 − e βµ)...
Special relativity is one of the most tested theories in physics. A central postulated of SR is that the speed of light is the same for all observers in inertial reference frames, and this leads to time dilation and the other effects that have been tested with a high degree of precision.
We...
Hello everyone
I've a question about the cosmic microwave background which my nephew asked me a couple of days ago. How much energy hits the Earth each year from the CMB? I'm assuming here that it is measurable in this way, but apologies if not.
Thanks in advance for your help.
Chris
Homework Statement
Okay, so the question seems really simple so I don't know what I'm missing
A satellite orbits at a fixed point above the Earth's equator. Assuming the Earth has uniform
density, radius R, and angular frequency of rotation, omega
Find an expression for eta, such that the...
Homework Statement
The Earth receives on average about 390 W m−2 of radiant thermal energy from the Sun, averaged over the whole of the Earth. It radiates an equal amount back into space, maintaining a thermal equilibrium that keeps the average temperature on Earth the same. Assuming the Earth...
If gravity is the warping of space, how does it work on Earth for us? Imagine a trampoline (the most common example for describing gravity) when a bowling ball is kept on a trampoline the weight of the ball forces the trampoline to stretch, but on our planet the gravity works downward on the...
Now before you excommunicate me, what I want to know is with all these sightings of galaxies 'within cooee' of the big bang, are they all in the same direction?
How far can we see in the opposite direction?
If we can see equidistant in both directions, would that not indicate that we are...
Homework Statement
How far would be a planet from the earth, when its period would be 2 years?
T = 2 years/730 days
a = 150*106km
Homework Equations
a3/T2 = C
(C is the Kepler-Constant)
The Attempt at a Solution
I tried inserting T in days and years, but I always get a wrong solution, since C...
Homework Statement
The value of g at a point P inside the Earth and at another point Q outside the Earth is g/2. Maximum possible distance in terms of radius of Earth between P and Q is? (g being the acceleration due to gravity on the surface).
Homework Equations
gh = (1+h/r)-2g...
Would the gravity of Earth decrease if the Earth stop spinning? Would the gravity be affected at all? Does the gravity of other orbiting bodies cause the Earth to speed up its rotation and slow down its rotation during the year? thanks.