On any clear night, the sky appears almost unchanged from what people have seen for hundreds of years.
But above our heads, the Earth is busier than ever.
According to the Union of Concerned Scientists and UNOOSA, there are currently over 10,000 energetic satellites in Earth orbit. It supports every part from GPS navigation and weather forecasts to web services and TV broadcasts.
So if hundreds of satellites are always orbiting the planet, why doesn’t the sky look crowded?
They are much smaller than you’re thinking that
The answer starts with size. Most satellites are surprisingly small. Many Earth remark satellites are as large as standard buses, while CubeSats may be as small as a shoebox.
Even large communications satellites are small in comparison with the large distances that separate them from observers on Earth.
At such distances, satellites cover an angle much smaller than the human eye can distinguish.
Imagine attempting to spot a grain of rice a whole bunch and even tens of hundreds of kilometers away. This is closer to the challenge our eyes face
Distance makes the most important difference
Not all satellites orbit at the identical altitude.
Low Earth orbit (LEO) extends to an altitude of roughly 2,000 kilometers above Earth. The International Space Station (ISS) orbits at a distance of about 400 kilometers, while most Starlink satellites operate at a distance of about 550 kilometers.
Because these satellites are relatively near Earth, they’ll sometimes be seen as vibrant objects moving steadily across the night sky.
On the opposite hand, the Geostationary Orbit (GEO) lies 35,786 kilometers above the Earth’s equator, which is nearly 90 times farther than the ISS. Many communications satellites, including Indonesia’s SATRIA-1, Malaysia’s MEASAT-3d, Thailand’s Thaicom, and Vietnam’s VINASAT-1 and VINASAT-2, operate at this altitude.
At this distance, even satellites with solar panels stretching tens of meters are just too small to be seen with the naked eye.
Why GEO satellites never move
Unlike satellites in LEO, which orbit the Earth every 90 to 100 minutes, satellites in GEO orbit at the exact same speed because the Earth rotates.
As a result, they seem to stay stationary above the identical point on the equator. This allows satellites comparable to SATRIA-1, MEASAT-3d, Thaicom and VINASAT to supply uninterrupted television, web and communications services using terrestrial antennas that never have to track their movements.
Why some satellites are visible
The reason why some satellites may be seen and others cannot isn’t only their size, but in addition their orbit and lighting conditions.
Satellites in LEO, comparable to the ISS and Starlink, are close enough to often reflect sunlight back to observers on the bottom, making them appear as vibrant stars moving steadily across the sky.
However, a lot of the communication satellites in GEO remain far beyond the range of human sight. Although they repeatedly transmit Internet connections, television broadcasts, and phone calls, they’re just too distant to reflect enough sunlight to be detected by the naked eye.
An invisible net above us
Although the night sky appears largely empty, it’s crammed with spacecraft that quietly support modern life.
Whether you utilize GPS navigation, watch satellite TV, check the weather or connect with broadband Internet, there’s a superb likelihood that satellite will make it possible for you.
Most remain invisible not because they should not there, but because they’re just too small and too distant for our eyes to see.
