Earth is the planet on which we live, the 3rd planet from the Sun. Questions using this tag should be about Earth the planet and not Earth-like planets nor earth, as in dirt or soil.

learn more… | top users | synonyms

4
votes
1answer
211 views

Why does the Sun turn red near sunset?

At daytime the Sun's light is yellowish if not near white. Why when the Sun starts to go down that it's light turn more red. I don't think the earth's rotation is so rapid to cause a red shift. Why ...
4
votes
2answers
309 views

Why aren't solar panels efficient?

Why can't solar panels produce 1 Kw per 1 square meter? This is the energy of the Sun's radiation per square meter on Earth but solar panels don't come close. Why can't we trap all that energy? ...
6
votes
4answers
1k views

If you could ride an elevator through the earth [duplicate]

What if it was possible to ride an elevator straight through earth. If we take all the heat and pressure problems away, and assume it would be possible: What would happen with gravity? Would gravity ...
1
vote
3answers
101 views

What is the constant $g_0$ used for calculating the specific impulse in seconds?

Wikipedia defines specific impulse as: $$ I_\mathrm{sp} = \frac{F_\mathrm{thrust}}{\dot{m} \cdot g_0} $$ The $g_0$ is said to be the acceleration at the Earth's surface. So is it actually the ...
1
vote
1answer
384 views

True or false: the Moon was touching the Earth 1.2 billion years ago

A creationist website makes this argument for the 6,000 year old earth. I'm embarrassed to say I don't know how to do the math to evaluate the claim myself. However, the time scales involved seems ...
5
votes
2answers
116 views

If Earth was the size of an orange, what consistency would it be? [closed]

I understand that the Earth is composed of a thin crust "floating" over a semi-solid layer of mantle. I was wondering how it would feel at a human scale, say the size of an orange in your hand. Could ...
15
votes
2answers
247 views

What would happen to wet laundry in the vacuum of space?

Imagine for a second that I was in a college dorm room frustrated that all the dryers were broken or in use. I'm impatient and not a jerk so I don't wait or take out someone else's laundry, I shoot it ...
1
vote
2answers
192 views

Earth's Temperature

I have a question regarding earth's temperature... How come the average temperature in the middle east (Israel, Saudi Arabia, Sudan or lower) is always so much significantly higher than in Europe ...
0
votes
1answer
257 views

Can gravity be reversed?

I'm wondering if any set of hypothetical conditions could result in us gravitating in a different direction. Specifically a reversal of gravity on the surface of Earth (or at least part of it), so ...
1
vote
1answer
114 views

Can we calculate the frame dragging force of the Earth?

Although clearly this force would be significantly greater with a rotating black hole, is it still possible to calculate this drag for say a satellite orbiting the Earth?
5
votes
2answers
671 views

Effect on length of day as the polar ice caps melt

If the polar ice caps of the earth melt, how will the length of the day be affected?
6
votes
2answers
379 views

Will I get a shock when I try to use my hair-dryer under water?

Occasionally people get killed in their bathtubs by having an electrical device such as a hair-dryer take the bath with them - in movies. It seems to be a common belief that this is realistic, even ...
116
votes
15answers
35k views

How do I explain to a six year old why people on the other side of the Earth don't fall off? [closed]

Today a friend's six year old sister asked me the question "why don't people on the other side of the earth fall off?". I tried to explain that the Earth is a huge sphere and there's a special force ...
2
votes
0answers
64 views

Why does the airflow in the mid-stratosphere of the northern hemisphere rotate FASTER than the earth?

I have been playing around with this nice visualisation and noticed that in the mid-stratosphere (P=10hPa), the airflow around the equator and south of it is in the opposite direction to the earth's ...
3
votes
2answers
72 views

why the shape or size of Magnetosphere is different both side?

Two days ago, I watched a documentary about solar flares, and how Magnetosphere protect us from that to earth. I was able to understand most of it, but I'm still curious to know why the ...
0
votes
1answer
122 views

Does the Earth's rotation affect an object in the stratosphere?

Does the Earth's rotation affect an object in the stratosphere? Example: I attach an object to a weather balloon and let it go at latitude +40.7, longitude -73.9 (New York). It goes up until it hits ...
0
votes
0answers
335 views

Gravity change as a function of time only

Is it possible to find how gravity changes with time? That is, height is not part of the equation. For example, $g$ can be expressed as a function of height that does not involve time with this ...
1
vote
3answers
2k views

No uncertainty for standard gravitational acceleration?

The other day I asked about the uncertainty of light, and this issue triggered me to start looking into other physical constants and try to understand why other constants have no uncertainty. One of ...
4
votes
1answer
726 views

Does the Earth rotate vertically too?

We know that the earth has seen several Ice Ages. And we know the Earth's magnetic poles seem to flip once in a while. Could all of this be explained by a once every 250 Million Years or so the ...
-4
votes
1answer
114 views

From where we can view earth moving?

Earth moves with a speed around $100000 \,\,km/h$, which will be amazing, but from where we can see that moving speed? If we far away from earth (outside of earth gravity) then can view its moving? is ...
4
votes
1answer
33 views

What weathering mechanism leads to reduction of Carbon Dioxide in the atmosphere?

Wikipedia says: The global temperature of the Earth will climb because of the rising luminosity of the Sun, the rate of weathering of silicate minerals will increase. This in turn will decrease ...
1
vote
1answer
89 views

What kind of damage is expected to happen to the earth in case of being hit by a direct gamma ray burst?

I understand how the ozone layer would be quickly depleted and the UV radiation from the sun would reach the ground...etc I understand all this, but what confuses me is where all this huge amount of ...
9
votes
1answer
392 views

How much does increased world population contribute to global warming?

In 1974 there where 4 billion people on earth. Now in 2013 we passed 7 billion people. So the world population is nearly doubled in 40 years. Every living human being also haves a body temperature of ...
2
votes
2answers
70 views

Energy loss of Earth

How does the Earth lose the energy that it gains from the sun's radiation if it is surrounded by - and in contact with - nothing?
4
votes
2answers
885 views

How is the Earth heated by a Full Moon?

While the moon is certainly not a good reflector of solar radiation, surely the radiation it reflects back heats the Earth (even if it is a terribly small amount). How would one go about calculating ...
13
votes
3answers
906 views

Is the total energy of earth changing with time?

Many years ego, Earth was hot. Over time, it has lost energy and has become colder. Is it now in equilibrium or is its total energy changing?
5
votes
1answer
145 views

How long did the first rainshowers on Earth last?

When I was a child, I read many times over with fascination about the formation of the Earth in a large illustrated encyclopedia of sorts for adults (one of at least two volumes, though I will ...
1
vote
2answers
162 views

Does earths gravitational force vary depending on where you are on the planet?

Does the gravitational force acting on a person ever change just by their position on the planet. For instance, at greater altitudes or closer to the equator.
0
votes
1answer
98 views

Will we gain some extra hours if we travel in the direction of the rotation of the earth? [closed]

I heard that If we travel for long distances in the direction of the rotation of the earth, we can gain some extra hours in the journey. Is it true? What if we travel in the opposite direction?
5
votes
2answers
385 views

Why does earth's magnetic field change its direction?

I know that the earth's magnetic field is due to molten metal and ions flowing in its core. It has been found that the Earth's magnetic field changes its direction and it has even flipped once! But, ...
-4
votes
1answer
213 views

Value of of gravity 9.8m/sec^2 and centrifugal force [closed]

I had a doubt regarding centrifugal force on earth is not accounted in any equations as object falling towards earth.eg f=ma.i read questions asked by few about the same and got to a conclusion that ...
7
votes
4answers
3k views

Does the moon affect the Earth's climate?

So, this morning I was talking to a friend about astronomical observations, and he told me that lately there has only been good weather when there was a full moon in the sky, which was a shame. I ...
2
votes
4answers
2k views

If there were no space between nuclei, how big would the Earth be?

I have some people telling me it would be the size of baseball. I am quite doubtful on this. If this is true, then the gaps must be so incredibly huge that everything should be transparent. I am not a ...
1
vote
3answers
4k views

Generator using Earths's Magnetic field?

In the past I've been shown Internet sources claiming a specific generator that uses nothing but the earth's magnetic field to generate power, I'm looking for the name of the generator? I realize ...
0
votes
2answers
154 views

What colour is the Earth?

More specifically, what shade of blue is the earth on average? I want to create an accurate earth-coloured blob in a simulation / presentation. A quick search didn't turn up anything. What I found ...
0
votes
1answer
109 views

How faster is the effect of force exerted by gravity? [duplicate]

We all know that Earth revolves around the Sun due to Gravitational force of the Sun. Also we know that it takes just over 8 minutes for the Sun's light to reach Earth. Now let us say, hypothetically ...
6
votes
2answers
251 views

Why are we not affected by the radiation of the radioactive decay going inside the Earth?

I was reading the question Why has Earth's core not become solid?, and one of the answers says that The core is heated by radioactive decays of Uranium-238, Uranium-235, Thorium-232, and ...
32
votes
3answers
2k views

Why has Earth's core not become solid?

The Earth is billions of years old, yet its core has not yet cooled down and become solid. Will this happen in the foreseeable future?
1
vote
1answer
606 views

What is the deepest man-made underground tunnel? [closed]

What is the deepest tunnel in the Earth's surface? I have meet numbers, around 300km. What is the main problem to make tunnel more deeper? What is the problem with 1000km?
15
votes
5answers
2k views

Can Helium Disappear from Earth?

Can Helium disappear? As we know Helium is lighter than air, so basically Helium fly off from Earth. Is it possible that in the future we will run out Helium?
0
votes
0answers
251 views

As the earth rotates around itself, does this have any effect on the dynamics of flights? [duplicate]

As the earth rotates around itself, does this have any effect on the dynamics of flights? Or "shouldn't" this have an effect? Does flying in the direction of the rotation of earth around itself, or ...
-5
votes
2answers
1k views

Finding the period of an infinite length pendulum [closed]

What would be the period of a pendulum with an infinite length, assuming a non-rotating Earth? The answer is not infinity.
6
votes
5answers
1k views

How much does the Earth's rotation affect a golf ball?

When launching rockets into space, they start straight but begin to lean, I assume due to the Earth's rotation. For something on a much smaller scale, such as a golf tee, is there a measurable ...
20
votes
3answers
830 views

Are the air particles in today's wind on earth (more or less) the same as the air 2/3 billion years ago?

So the air pressure on earth remains relatively constant, right? Is there air gained or lost through transitions of any sort? e.g. plumes going out into space, earth gaining new air particles with ...
4
votes
2answers
3k views

What is the scientific reason for the inclination of earth's rotation axis?

This titled position of the earths axis is known as inclination of the earths axis. The earth's rotation axis makes an angle of about 66.5 degrees with the plane of its orbit around the sun, or about ...
-2
votes
1answer
194 views

Calculation of 12000 Lunar Orbits/Earth Day [closed]

I am really interested in the calculation of the following speed value in meter-per-second unit: Speed of something that is able to travel in one earth day the distance that it would take for the ...
2
votes
1answer
79 views

Does the sun's bearing at a given time vary, and if so, how?

More an astronomy question, but Physics is the closest stack exchange category I could find and Google doesn't have the answer. Granted, the sun's elevation changes for a given time of day throughout ...
1
vote
1answer
147 views

Why does earth spins? [duplicate]

I understand the governing force causing the earth's cycle around the sun is gravity. It can be described by Keplar's law. But what causes the earth's spin? what is its governing law?
18
votes
2answers
2k views

How long until we fall into the Sun?

As a planet moves through the solar system, a bow shock is formed as the solar wind is decelerated by the magnetic field of the planet. Presumably the creation of this shock wave would cause drag on ...
2
votes
0answers
41 views

Computing Latitude Given Quiescent Gyroscope Data

Suppose I place a gyroscope in a theoretically perfectly quiescent, closed room. Let its output be given as a vector ${\bf v} = (v_x, v_y, v_z)$ indicating rate of rotation around three orthogonal ...