KingJudah2
All Star
A theory is not a fact. I think you need to go back to school. Like I said a theory is "this the best we could do" in science. How come the "southern hemisphere" has more gravity than the northern?
Draymond thinks earth could be flat
- Thread starter Randoug
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The Odum of Ala Igbo
Hail Biafra!
the southern hemisphere does not have "more gravity" than the northern hemisphere. the force of gravity can vary across the earths surface depending on different things such as the distance you are from the core of the earth. Gravitational force variances are predictable and measurable by mathematics. It's not some breakdown in the theory. I need to go back to school? I'm the one who knows what the fukk they're talking about here. If you want to say that scientific theories aren't correct and it's just some "best guess" by scientists then why should I even listen to a single word you say? I sure as hell know you aren't smarter than the people who discover/test/replicate scientific theory.
KingJudah2
All Star
Site a study (find me an abstract) that demonstrably proves gravitational force varies. The only thing that varies are oxygen levels, which modify the effect of density and volume of objects in their environment. It was a rhetorical question. If gravity was indeed a fact, not a theory. The southern hemisphere would in fact, need more gravity than the northern hemisphere. Unless the earth is a plane, which then would mean at sea level regardless of position on earth, would have the same exact force.
Variation in gravity and apparent gravity[edit]
A perfect sphere of uniform mass density, or whose density varies solely with distance from the centre (spherical symmetry), would produce a gravitational field of uniform magnitude at all points on its surface, always pointing directly towards the sphere's centre. The Earth is not spherically symmetric, but is slightly flatter at the poles while bulging at the Equator: an oblate spheroid. There are consequently slight deviations in both the magnitude and direction of gravity across its surface. The net force (or corresponding net acceleration) as measured by a scale and plumb bob is called "effective gravity" or "apparent gravity". Effective gravity includes other factors that affect the net force. These factors vary and include things such as centrifugal force[3] at the surface from the Earth's rotation and the gravitational pull of the Moon and Sun.
Effective gravity on the Earth's surface varies by around 0.7%, from 9.7639 m/s2 on the Nevado Huascarán mountain in Peru to 9.8337 m/s2 at the surface of the Arctic Ocean.[4] In large cities, it ranges from 9.766 in Kuala Lumpur, Mexico City, and Singapore to 9.825 in Oslo and Helsinki.
Latitude[edit]
The differences of Earth's gravity around the Antarctic continent.
The surface of the Earth is rotating, so it is not an inertial frame of reference. At latitudes nearer the Equator, the outward centrifugal force produced by Earth's rotation is larger than at polar latitudes. This counteracts the Earth's gravity to a small degree – up to a maximum of 0.3% at the Equator – and reduces the apparent downward acceleration of falling objects.
The second major reason for the difference in gravity at different latitudes is that the Earth's equatorial bulge (itself also caused by centrifugal force from rotation) causes objects at the Equator to be farther from the planet's centre than objects at the poles. Because the force due to gravitational attraction between two bodies (the Earth and the object being weighed) varies inversely with the square of the distance between them, an object at the Equator experiences a weaker gravitational pull than an object at the poles.
In combination, the equatorial bulge and the effects of the surface centrifugal force due to rotation mean that sea-level effective gravity increases from about 9.780 m/s2 at the Equator to about 9.832 m/s2 at the poles, so an object will weigh about 0.5% more at the poles than at the Equator.[3][5]
The same two factors influence the direction of the effective gravity (as determined by a plumb line or as the perpendicular to the surface of water in a container). Anywhere on Earth away from the Equator or poles, effective gravity points not exactly toward the centre of the Earth, but rather perpendicular to the surface of the geoid, which, due to the flattened shape of the Earth, is somewhat toward the opposite pole. About half of the deflection is due to centrifugal force, and half because the extra mass around the Equator causes a change in the direction of the true gravitational force relative to what it would be on a spherical Earth.
Altitude[edit]
The graph shows the variation in gravity relative to the height of an object
Gravity decreases with altitude as one rises above the Earth's surface because greater altitude means greater distance from the Earth's centre. All other things being equal, an increase in altitude from sea level to 9,000 metres (30,000 ft) causes a weight decrease of about 0.29%. (An additional factor affecting apparent weight is the decrease in air density at altitude, which lessens an object's buoyancy.[6] This would increase a person's apparent weight at an altitude of 9,000 metres by about 0.08%)
It is a common misconception that astronauts in orbit are weightless because they have flown high enough to escape the Earth's gravity. In fact, at an altitude of 400 kilometres (250 mi), equivalent to a typical orbit of the Space Shuttle, gravity is still nearly 90% as strong as at the Earth's surface. Weightlessness actually occurs because orbiting objects are in free-fall.[7]
The effect of ground elevation depends on the density of the ground (see Slab correction section). A person flying at 30 000 ft above sea level over mountains will feel more gravity than someone at the same elevation but over the sea. However, a person standing on the earth's surface feels less gravity when the elevation is higher.
The following formula approximates the Earth's gravity variation with altitude:
{\displaystyle g_{h}=g_{0}\left({\frac {r_{\mathrm {e} }}{r_{\mathrm {e} }+h}}\right)^{2}}
Where
- gh is the gravitational acceleration at height h above sea level.
- re is the Earth's mean radius.
- g0 is the standard gravitational acceleration.
Depth[edit]
See also: Shell theorem
An approximate value for gravity at a distance r from the centre of the Earth can be obtained by assuming that the Earth's density is spherically symmetric. The gravity depends only on the mass inside the sphere of radius r. All the contributions from outside cancel out as a consequence of the inverse-square law of gravitation. Another consequence is that the gravity is the same as if all the mass were concentrated at the centre. Thus, the gravitational acceleration at this radius is[8]
{\displaystyle g(r)=-{\frac {GM(r)}{r^{2}}}.}
where G is the gravitational constant and M(r) is the total mass enclosed within radius r. If the Earth had a constant density ρ, the mass would be M(r) = (4/3)πρr3 and the dependence of gravity on depth would be
{\displaystyle g(r)={\frac {4\pi }{3}}G\rho r.}
g at depth d is given by g'=g(1-d/R) where g is acceleration due to gravity on surface of the earth, d is depth and R is radius of Earth. If the density decreased linearly with increasing radius from a density ρ0 at the centre to ρ1 at the surface, then ρ(r) = ρ0 − (ρ0 − ρ1) r / re, and the dependence would be
{\displaystyle g(r)={\frac {4\pi }{3}}G\rho _{0}r-\pi G\left(\rho _{0}-\rho _{1}\right){\frac {r^{2}}{r_{\mathrm {e} }}}.}
The actual depth dependence of density and gravity, inferred from seismic travel times (see Adams–Williamson equation), is shown in the graphs below.
Earth's radial density distribution according to the Preliminary Reference Earth Model (PREM).[9]
Earth's gravity according to the Preliminary Reference Earth Model (PREM).[9] Two models for a spherically symmetric Earth are included for comparison. The dark green straight line is for a constant density equal to the Earth's average density. The light green curved line is for a density that decreases linearly from centre to surface. The density at the centre is the same as in the PREM, but the surface density is chosen so that the mass of the sphere equals the mass of the real Earth.
Local topography and geology[edit]
See also: Physical geodesy
Local differences in topography (such as the presence of mountains), geology (such as the density of rocks in the vicinity), and deeper tectonic structure cause local and regional differences in the Earth's gravitational field, known as gravitational anomalies.[10] Some of these anomalies can be very extensive, resulting in bulges in sea level, and throwing pendulum clocks out of synchronisation.
The study of these anomalies forms the basis of gravitational geophysics. The fluctuations are measured with highly sensitive gravimeters, the effect of topography and other known factors is subtracted, and from the resulting data conclusions are drawn. Such techniques are now used by prospectors to find oil and mineral deposits. Denser rocks (often containing mineral ores) cause higher than normal local gravitational fields on the Earth's surface. Less dense sedimentary rocks cause the opposite.
Other factors[edit]
In air, objects experience a supporting buoyancy force which reduces the apparent strength of gravity (as measured by an object's weight). The magnitude of the effect depends on air density (and hence air pressure); see Apparent weight for details.
The gravitational effects of the Moon and the Sun (also the cause of the tides) have a very small effect on the apparent strength of Earth's gravity, depending on their relative positions; typical variations are 2 µm/s2 (0.2 mGal) over the course of a day.
KingJudah2
All Star
yuh yankees lazy ras. Thats why we West Indians and Africans gonna run things here, lazy thinkers. Chinese already running you yankees
you're mentally retarded
KingJudah2
All Star
I said demonstrable. How does someone "feel" more gravity over sea than land. This should be demonstrable via experiment. Btw all stated about can be proven with density and volume alone. Gravity doesn't even have to factor in. Seems as if scientists don't even know what gravity really is.Variation in gravity and apparent gravity[edit]
A perfect sphere of uniform mass density, or whose density varies solely with distance from the centre (spherical symmetry), would produce a gravitational field of uniform magnitude at all points on its surface, always pointing directly towards the sphere's centre. The Earth is not spherically symmetric, but is slightly flatter at the poles while bulging at the Equator: an oblate spheroid. There are consequently slight deviations in both the magnitude and direction of gravity across its surface. The net force (or corresponding net acceleration) as measured by a scale and plumb bob is called "effective gravity" or "apparent gravity". Effective gravity includes other factors that affect the net force. These factors vary and include things such as centrifugal force[3] at the surface from the Earth's rotation and the gravitational pull of the Moon and Sun.
Effective gravity on the Earth's surface varies by around 0.7%, from 9.7639 m/s2 on the Nevado Huascarán mountain in Peru to 9.8337 m/s2 at the surface of the Arctic Ocean.[4] In large cities, it ranges from 9.766 in Kuala Lumpur, Mexico City, and Singapore to 9.825 in Oslo and Helsinki.
Latitude[edit]
The differences of Earth's gravity around the Antarctic continent.
The surface of the Earth is rotating, so it is not an inertial frame of reference. At latitudes nearer the Equator, the outward centrifugal force produced by Earth's rotation is larger than at polar latitudes. This counteracts the Earth's gravity to a small degree – up to a maximum of 0.3% at the Equator – and reduces the apparent downward acceleration of falling objects.
The second major reason for the difference in gravity at different latitudes is that the Earth's equatorial bulge (itself also caused by centrifugal force from rotation) causes objects at the Equator to be farther from the planet's centre than objects at the poles. Because the force due to gravitational attraction between two bodies (the Earth and the object being weighed) varies inversely with the square of the distance between them, an object at the Equator experiences a weaker gravitational pull than an object at the poles.
In combination, the equatorial bulge and the effects of the surface centrifugal force due to rotation mean that sea-level effective gravity increases from about 9.780 m/s2 at the Equator to about 9.832 m/s2 at the poles, so an object will weigh about 0.5% more at the poles than at the Equator.[3][5]
The same two factors influence the direction of the effective gravity (as determined by a plumb line or as the perpendicular to the surface of water in a container). Anywhere on Earth away from the Equator or poles, effective gravity points not exactly toward the centre of the Earth, but rather perpendicular to the surface of the geoid, which, due to the flattened shape of the Earth, is somewhat toward the opposite pole. About half of the deflection is due to centrifugal force, and half because the extra mass around the Equator causes a change in the direction of the true gravitational force relative to what it would be on a spherical Earth.
Altitude[edit]
The graph shows the variation in gravity relative to the height of an object
Gravity decreases with altitude as one rises above the Earth's surface because greater altitude means greater distance from the Earth's centre. All other things being equal, an increase in altitude from sea level to 9,000 metres (30,000 ft) causes a weight decrease of about 0.29%. (An additional factor affecting apparent weight is the decrease in air density at altitude, which lessens an object's buoyancy.[6] This would increase a person's apparent weight at an altitude of 9,000 metres by about 0.08%)
It is a common misconception that astronauts in orbit are weightless because they have flown high enough to escape the Earth's gravity. In fact, at an altitude of 400 kilometres (250 mi), equivalent to a typical orbit of the Space Shuttle, gravity is still nearly 90% as strong as at the Earth's surface. Weightlessness actually occurs because orbiting objects are in free-fall.[7]
The effect of ground elevation depends on the density of the ground (see Slab correction section). A person flying at 30 000 ft above sea level over mountains will feel more gravity than someone at the same elevation but over the sea. However, a person standing on the earth's surface feels less gravity when the elevation is higher.
The following formula approximates the Earth's gravity variation with altitude:
{\displaystyle g_{h}=g_{0}\left({\frac {r_{\mathrm {e} }}{r_{\mathrm {e} }+h}}\right)^{2}}
Where
The formula treats the Earth as a perfect sphere with a radially symmetric distribution of mass; a more accurate mathematical treatment is discussed below.
- gh is the gravitational acceleration at height h above sea level.
- re is the Earth's mean radius.
- g0 is the standard gravitational acceleration.
Depth[edit]
See also: Shell theorem
An approximate value for gravity at a distance r from the centre of the Earth can be obtained by assuming that the Earth's density is spherically symmetric. The gravity depends only on the mass inside the sphere of radius r. All the contributions from outside cancel out as a consequence of the inverse-square law of gravitation. Another consequence is that the gravity is the same as if all the mass were concentrated at the centre. Thus, the gravitational acceleration at this radius is[8]
{\displaystyle g(r)=-{\frac {GM(r)}{r^{2}}}.}
where G is the gravitational constant and M(r) is the total mass enclosed within radius r. If the Earth had a constant density ρ, the mass would be M(r) = (4/3)πρr3 and the dependence of gravity on depth would be
{\displaystyle g(r)={\frac {4\pi }{3}}G\rho r.}
g at depth d is given by g'=g(1-d/R) where g is acceleration due to gravity on surface of the earth, d is depth and R is radius of Earth. If the density decreased linearly with increasing radius from a density ρ0 at the centre to ρ1 at the surface, then ρ(r) = ρ0 − (ρ0 − ρ1) r / re, and the dependence would be
{\displaystyle g(r)={\frac {4\pi }{3}}G\rho _{0}r-\pi G\left(\rho _{0}-\rho _{1}\right){\frac {r^{2}}{r_{\mathrm {e} }}}.}
The actual depth dependence of density and gravity, inferred from seismic travel times (see Adams–Williamson equation), is shown in the graphs below.
Earth's radial density distribution according to the Preliminary Reference Earth Model (PREM).[9]
Earth's gravity according to the Preliminary Reference Earth Model (PREM).[9] Two models for a spherically symmetric Earth are included for comparison. The dark green straight line is for a constant density equal to the Earth's average density. The light green curved line is for a density that decreases linearly from centre to surface. The density at the centre is the same as in the PREM, but the surface density is chosen so that the mass of the sphere equals the mass of the real Earth.
Local topography and geology[edit]
See also: Physical geodesy
Local differences in topography (such as the presence of mountains), geology (such as the density of rocks in the vicinity), and deeper tectonic structure cause local and regional differences in the Earth's gravitational field, known as gravitational anomalies.[10] Some of these anomalies can be very extensive, resulting in bulges in sea level, and throwing pendulum clocks out of synchronisation.
The study of these anomalies forms the basis of gravitational geophysics. The fluctuations are measured with highly sensitive gravimeters, the effect of topography and other known factors is subtracted, and from the resulting data conclusions are drawn. Such techniques are now used by prospectors to find oil and mineral deposits. Denser rocks (often containing mineral ores) cause higher than normal local gravitational fields on the Earth's surface. Less dense sedimentary rocks cause the opposite.
Other factors[edit]
In air, objects experience a supporting buoyancy force which reduces the apparent strength of gravity (as measured by an object's weight). The magnitude of the effect depends on air density (and hence air pressure); see Apparent weight for details.
The gravitational effects of the Moon and the Sun (also the cause of the tides) have a very small effect on the apparent strength of Earth's gravity, depending on their relative positions; typical variations are 2 µm/s2 (0.2 mGal) over the course of a day.
KingJudah2
All Star
quiet duppy boy
it seems like you have a natural distrust for intellectual authority and are slightly stupid/retarded. How about your stupid ass prove anything that you've been babbling about? Why is the burden of proof on me to disprove hundreds/thousands of years of scientific rigor? How about you demonstrably prove any of the stupid shyt you say?
KingJudah2
All Star
when Intellectual authority say "trust us we can't prove anything we're saying but we're the authority so trust us" is when everybody need to hold dem people accountable. Simply trusting authority because they authorities is a weakness.
Btw are you a psychologist? Stick to the topic nobody talking about personal shyt to bolster arguments
You clearly don't understand the process that a hypothesis takes to become an accepted scientific theory. People don't just make ideas up with no proof and have them become an accepted scientific theory. It's an extremely rigorous process for a hypothesis to become a scientific theory.
KingJudah2
All Star
Even then it's still a theory. There have been theories that have been thought to be bulletproof, when repeated at later dates, not looking for confirmations, failed. "Scientists" look for confirmations which is a bias. Especially modern science. Scientists aren't even challenging existing theories just building on them. Sandcastle science.
mbewane
Knicks: 93 til infinity
Breh let this die, there is absolutely nothing you can do to convince people who have their mind made up. Like you said, for some reason the burden of proof is on on you, like you're supposed to know centuries of science by heart. But Earth-flatters somehow don't have to prove anything, they say "we're just asking questions" lol...very handy. Whatever proof you provide they will question the source, say it's a conspiracy, etc. There is absolutely NOTHING you can tell them that will change their belief, even if you gather 45000 scientists of all countries they will just say it' a global conspiracy and that you're sheep
so what are you building then? sandcastle retardation?
