The stunning new photos of the pillars of creation are made even more stunning when you consider the massive scale – 5 light years tall, 6500 light years away. How do we get photos of something that takes 6500 years for the light/image to reach us ?
EDIT: ya’ll I feel silly now after having a day to think about this. I’ll blame my initial confusion on sleep deprivation. Goodnight.
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There is (almost) nothing between our telescope and the object so the light continues unobstructed. On Earth, the molecules in the air scatter the light from objects that are far away.
Also, we are seeing it as it looked 6,500 years ago.
The distance is only an issue in the sense that the light is very dim and red-shifted. So we just need equipment that is sensitive enough to pick it up, and designed to detect light that is shifted toward that end of the spectrum (e.g. infrared).
Essentially just really sensitive equipment. The camera sensors of JWST, or Hubble, or any other space telescope work in a similar way to our regular cameras, but they’re considerably more sensitive. That means they pick up a lot more photons, which is necesary since theres very little light reaching us from those objects. They also have really big lenses because the wider the lens, the more light it will capture. Lastly, they usually have very long exposures, which means they’re collecting photons for a long time for each picture. Its the exact same as long exposure photos that we do on Earth. Theres not much more to it on a basic level, the really hard part is getting that sensitivity out of the equipment.
The light takes time to travel to the camera so we are seeing lights of the past. If we were to travel to the light source as it is now, it would likely look much different from what we see.
same way we take any photo: we point the camera at it, and press the button.
If it “takes 6500 years for the light/image to reach us”, the photo shows how the thing looked like 6500 years ago. it might look different now (e.g. if a star went supernova i.e. blew up), but we will not know until light from that event reaches us.
On Earth, you cannot take good pictures of far things because there is lots of air between the camera and the thing, and air often blurs images because of fog/smoke/heat ripples/etc. But there is no air in space. There are dust or gas clouds that block our view, but they are rare. In fact, pillars of creation are such a cloud.
The photons that we are picking up were released and sent our direction 6500 ly ago. They’ve been traveling and traveling for all that time. And when they get here, 6500 years later the telescope picks them up.
Technically EVERYTHING you see happened in the past. Even this reply took time for the photons from you monitor to get to your eye. In this case it’s nearly instantaneous since you’re so close and light travels so fast. But technically, you’re viewing the past.
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