Why do images of earth from space not contain satellites and other space junk?



Why do images of earth from space not contain satellites and other space junk?

In: Earth Science

I think you’re really underestimating how big Earth and the space around it are, and how small those things are in comparison. Also for image satellites it might be more desirable to pick a lower orbit, where there’s less of this stuff in the way. On the off chance that something *is* in the way, they might discard the photo and get another one on the next pass.

Another thing is there are around 34,000 peice of space junk larger then 10 centimeter most of those are tracked and catalog.so we are not talking about the first stage of a Saturn V rocket we are talking here small pecies of things. Each one of these have an orbit that can be tracked and monitored. So say that you have a debris field of space junk at altitude 100 miles above the earth’s surface you would program you satellite to avoid that area. Spacecraft the pilot would do this. So first you are already avoiding the area that junk is in and then you want to take a picture of the earth’s surface you point the camera towards the earth and take the picture while having avoided ever being near the debris in the first place. There have been times when debris has been captured on film. Look up the black night satellite for a good read. Also the camera resolution along with lighting angle of the sun shadows might not be able to illuminate the debris near you. Hope that helps.
*edit due to spelling.

Why do photos taken from your phone don’t contain every spec of dust in between the camera and the subject?

As explained by others, they’re either too small to even be caught by the camera, or when they do photobomb a picture they’re just discarded

It’s a bit like saying “why don’t you see people in images of the earth?” There’s some huge scales going on here.

Think about a mini van. That’s about the size of some satellites, but a good reference point. Some space junk is bigger and a whole lot is smaller.

Ever been in an airplane and looked out the window? That’s 40,000 feet (about 7-8 miles). Could you see a mini van on the ground from that distance? Nope.

Low Earth orbit starts at about 150miles up. The diameter of Earth is almost 8,000 miles. So to get a full picture of the Earth you have to be far away, and all the objects orbiting Earth (except the moon) are infinitesimally small in comparison.

It’s kinda like the “great plastic patch” in the ocean, it’s there but you can’t easily see it.

Answer this: “Why do images of Earth from space not contain trucks?”

Because they’re too small and spread out, right?

Except there are way more trucks than satellites, AND each truck is bigger too! So you’ve answered your own question. They’re smaller than a pixel in a pic that fits the whole earth.

>Space is big. You just won’t believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it’s a long way down the road to the chemist’s, but that’s just peanuts to space.

– The Hitchhiker’s Guide to the Galaxy

The shortest answer I can give you is because of distance.

**The farther the distance and the smaller the object, the more you can’t exactly see the object in a picture.**

Satellites and space junk are too far from each other to be taken in a picture. Space is extremely big.

Why do picture of a mountain not include birds??

Why do pictures of your hand not include the atoms??

ELI5 If there are one million ants per human on earth, why can’t I see them from my window seat on a flight?

I am one of those newspace satellite engineers, specializing in developing the EO payloads.

The distance argument is the strongest one, but there is also the factor of light. The lighting conditions have to be just perfect, angle of sunlight, the shape and surface on the debris and camera position. The smaller size does not actually matter when there is perfect reflection as that would still fill the pixel up. Think taking a long exposure of the sky, the star is smaller than a pixel but still can be seen in the image. This is true as the background is the void of space, not the case when looking at Earth. It can still happen that the background is well lit and the debris is seen as a dark spot.

A 10cm debris at 300km being imaged at 400km orbit from a satellite that is doing 30cm resolution on earth would surely see it. But most often it would happen over sea or such where the earth image is not of use. Besides, most satellites do 20m – 1000m resolutions, the sub-meter things are very few, and they will have more problems when there are 60000 new satellites up there. But lighting conditions are still important to actually affect the data meaningfully. The problem is much worse for telescopes on ground as they have really high resolution and smallest of the debris can light up with even a fraction of the light. There is a [study](https://astronomy.com/news/2021/04/satellite-skyglow-may-mean-light-pollution-is-unavoidable) that says, they would eventually even reflect man-made light going off earth.

Space debris and the rising ammount of satellites is a real concern in astronomy, despite being small they have shinny surfaces that reflect the sun and can pollute the observations towards the space. But in the opposite case the Earth is reflecting much more light than any artificial satellite, effectively hiding them just like the sunlight hides all the other stars during the day.

They’re fucking tiny… Photos taken from geostationary profit that’s high enough to see the whole earth have a resolution of at best 1/3rd of a mile per pixel, meaning youd really need a sat half a mile across to spot at low profit, low earth says that photograph for maps and such are below most other days and statistically it’s near impossible another would be in shot during a photo, shots taken from space stations are wide angle so a sat would have to be within a km or so to be visible and there just isn’t a density of days like that

Everyone else has given great answers, but [here’s an example](https://www.diyphotography.net/cameras-on-the-international-space-station-capture-spacex-starlink-satellite-train-over-an-aurora/) where satellites **were** photographed from the ISS under fortunate conditions!

As others have mentioned, the Earth is big – real big compared to a satellite. In order to get a picture of the entire Earth at once you need to be pretty far away – to the order of thousands of kilometers.

Geostationary orbit is about 35,000 kilometers or 22,000 miles away from the earth as an example.

Most satellites or “space junk” are maybe the size of a car. Imagine looking at a car from a mile away. Then ten miles, a hundred miles, a thousand miles.

You can see the Earth because it is huge, but that car floating in the void thousands of miles away? Not a chance.

There are (very roughly) 10,000 satellites orbiting the earth. There are about 200,000 Ferraris in the world. Twenty times as many! How many photos of earth contain an identifyable Ferrari?

Space is really big and satellites are really small.

While there is a lot of stuff orbiting the planet, typically there are miles and miles between each object. It’s like driving down a country road in the middle of the night. There’s no one around for miles.

Space is absolutely huge beyond our comprehension, forgive my French but it’s a Big Ass Sky! If you do the math the chances of hitting a piece of space junk is very slim!