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Have you ever looked up and found a twinkling star-like object traveling in a straight line across the night sky? How about a train of lights trailing in one direction? Well, they were probably satellites.
According to the USC Satellite Database, as of January 1st, 2022, our planet is orbited by 4,852 active manmade satellites. If you stare into the night sky long enough, you’re bound to see one.
We’ve made a list of 10 interesting facts about satellites to help you learn more about things like Sputnik 1, Elon Musk’s Starlink program, and how cannonballs relate to satellites.
Newton’s cannonball is the name given to a thought experiment by scientist Issac Newton, in which he visualized how an object could be thrown into orbit.
Here is a simplified version of his hypothesis:
If you were to stand on a mountain and throw an object, such as a stone or a cannonball, up into the air, and there was no gravity or resistance, then the object would simply keep going in the direction you threw it.
When you factor the Earth’s gravity, then depending on the velocity in which you threw the object, it could follow a different path.
If the speed at which the object is thrown or fired is not great, then the object will simply fall back down to earth.
If the velocity was too great, then the object might escape Earth’s gravity, and float off into space.
If the speed of the hypothetical cannonball or stone was to match the orbital speed at that altitude, then the object will be caught in Earth’s orbit, because its momentum and Earth’s gravity would constantly balance each other out.
In 1957, the Soviet Union launched the first satellite into Earth’s orbit.
Sputnik 1 was an aluminum ball. It was a small satellite, measuring just 23 inches in diameter, and weighing just above 184 lbs. It used a radio transmitter to send back electromagnetic waves, and it was designed by a scientist named Sergei Korolev.
The launch of Sputnik 1, and the subsequent launch a month later of Sputnik 2, surprised the western world. Soon after, NASA was created and there was an overhaul in education across the US, with American schools putting more emphasis on maths and science.
We use satellites so often in our daily lives, that we might not even realize how much we, as humans, depend on them.
The purpose of each satellite will dictate which orbit would be best for it, but there are 4 common orbit types:
Most modern satellites are equipped with big solar panels that look a little bit like wings. They convert light from the sun into an electric current that’s used to power the satellite. Satellites are also equipped with a battery to store any excess power that they harness.
When the satellite is traveling over the dark side of the earth, it will use the power from its batteries instead.
In order to remain in low earth orbit, a satellite must travel at 17,450 miles per hour. However, the farther the orbit from the earth, the slower the satellite will need to travel. A geostationary satellite only travels at a speed of 6,858 miles per hour.
To understand the relation, we refer to Newton’s cannonball theory. Objects which are in space are constantly falling because of Earth’s gravity. The closer the object is to Earth, the stronger that gravity becomes. For this reason, satellites that are closer to Earth must maintain a higher momentum, or risk falling!
Though some satellites now have incredibly long lifetimes, they are still man-made objects of metal and electronics, and at some point, whether it’s through old age or malfunctions, satellites will become non-operational.
When this happens, the satellites are disposed of in one of two ways. Low orbit satellites decrease in speed, at which point they begin to fall towards Earth, and burn up in the atmosphere. For very high-altitude satellites, it’s easier to point them farther away from Earth, so they fall out of orbit and float into space.
However, not all low earth satellites burn up in the Earth’s atmosphere, and so when it comes to larger satellites or spacecraft, operators plan for the descent and entry of any left-over debris to fall over the most remote place on Earth, as possible. This area is in the south Pacific Ocean, and it’s known as Spacecraft Cemetery.
Unfortunately, the satellites we send further away from Earth contribute to a growing space junk problem, which may need to be addressed in the future.
Starlink is the ambitious project by Elon Musk, to create a constellation of satellites around the Earth, to provide fast, global internet access, even in remote areas.
The company had initially planned to send 12,000 satellites into space, but in 2019 it appeared they hoped to send up to another 30,000.
Starlink satellites appear in the night sky like a train of tiny stars, moving at a relatively fast speed.
On the one hand, satellites really are helping us to advance in many ways. But some scientists and astronomers fear that the sheer number of satellites that are orbiting our planet will negatively impact our ability to observe the sky, and space, from the earth.
Many options have been discussed on how to minimize this impact, ranging from suggestions of darkening satellites or using sunshades to darken their reflective surfaces, to making more accurate orbital data and information available, so that astronomers on Earth can avoid pointing telescopes at them.
Satellites provide us with incredible pictures and information about our planet, but there are also Mars orbiters and the Cassini spacecraft that orbited Saturn. These orbiters take images and provide us with information and data about other planets in our solar system.
Nasa’s Mars Reconnaissance Orbiter has been used for over 16 years to scan the planet for weather data, capture images of the red planet, and scout possible future landing locations.
Satellites play important roles in our everyday lives, and currently, there are so many in Earth’s orbit, that you should be able to spot them easily in the night sky. There are even satellite tracker apps on the market that you can use on your smartphone to track, spot, and identify man-made satellites as they fly overhead.
But there are problems that need to be solved when it comes to satellites, such as finding ways to reduce the light that they reflect toward Earth and coming up with new ways to reduce the growing contribution of disused satellites to an already massive space junk issue.
Featured Image Credit: PIRO4D, Pixabay
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Cheryl is a freelance content and copywriter from the United Kingdom. Her interests include hiking and amateur astronomy but focuses her writing on gardening and photography. If she isn't writing she can be found curled up with a coffee and her pet cat.
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