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Travel A road trip in Burgundy reveals far more than fine wine. Travel My Hometown In L. Travel The last artists crafting a Thai royal treasure. Subscriber Exclusive Content. It comes up quite often. If you ask the people around you, there are two common answers:.
Astronauts float around in space because there is no gravity in space. Everyone knows that the farther you get from Earth, the less the gravitational force is. Well, astronauts are so far from the Earth that gravity is so small.
This is why NASA calls it microgravity. In space, no one can hear you scream. You know why? Because there is no air in space. No air, no sound. No air, no gravity. What is the gravitational force? It is an interaction between objects that have mass.
The Earth has mass and the astronaut has mass - so they are attracted. We can model this attractive force with the following expression. In this model for the magnitude of the gravitational force, M 1 and m 2 are the masses and r is the distance between the centers of these two masses.
G is the gravitational constant. It has a value of 6. Check this out. If I have something sitting on the ground, it interacts with the Earth. The mass of the Earth is 5. Let me put these values into the gravitational model. Yes, that is not 9. I used rounded values in the calculation so that it is off just a bit.
But you get the idea. I am getting off track here. Doesn't this expression say that the gravitational force gets weaker as you get farther from the Earth? But not by has much as you think.
A typical height for an orbiting Space Shuttle is about km above the surface of the Earth. Suppose I have a 75 kg astronaut. What would be the weight gravitational force on the astronaut both on the surface and in orbit? The only difference will be the distance between the astronaut and the center of the Earth. Enough to call it "weightless"? So, this isn't the correct explanation for "weightlessness". You can probably find some examples of why this isn't the cause of "weightlessness".
Here is one that I like. Anthony is a technology junkie that has vast experience in computer systems and automobile mechanics, as opposite as those sound. DEC 11, Cosmic Expansion: Universe Stretches, We don't. Physicists believe that we exist in an expanding universe.
But what does that mean? Written By: Daniel Duan. JAN 17, Astronomers Discover Planet with 3 Suns. Having just one star in our solar system makes us an outlier in our galaxy. However, while most solar systems in the Mil Written By: Annie Lennon.
MAR 05, Scientists Heal Diseased Corals. The world's coral reefs face numerous threats, including climate change, pollution, and habitat loss. It is difficult to imagine situations where we are not attracted to the Earth.
Absence of gravity is known as weightlessness. It is like floating, the feeling you get when a roller coaster suddenly goes down. Astronauts on the International Space Station are in free fall all the time. Gravity still pulls on the Station, but because it travels around the Earth at such high speed, its travelling forwards equals out the falling and the ISS stays more or less at the same height.
The astronauts inside it experience weightlessness, floating around in no particular direction.
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