Understanding The Webb Telescope Images
I still haven't seen the latest images, but I have looked at the one released yesterday. I was talking about it this morning with my wife, and it occurs to me that many people won't understand what to take from the images that show up today. So, here are some things to keep in mind:
1. The images are a view into the past, not a snapshot of the present. If you know how distant a feature your seeing is, in light years, you know how old the light you're looking at is. If a galaxy is 8 billion light years away, it means that the feature you're seeing is as it was 8 billion years ago. In many cases, it doesn't still even exist, nor it is now where it appears to be in the photo.
2. A light year is a measure of distance. One light year is roughly 6 trillion miles. For example, our solar system's sun is approximately 94 million miles from Earth. It takes just over 8 minutes for light from the sun to reach earth, so the sun you see is the sun as it was about 8 minutes and twenty seconds ago. It is 8 and a third light minutes away.
3. All of the features you see in the images are at different distances from here. Webb is capturing light from everywhere in the tiny little window of space it can see. So, each object or feature has to be identified and its distance measured before we know how old it is, which is also how far away it is, times 6 trillion, in miles.
4. We cannot travel to those places, and since the images are millions or billions of years old, those features are not where they appear to be now, assuming they exist at all now, which many of them do not.
5. Finally, what we're looking at is the history of the universe, not its present state. That is the most important fact to remember as you look at those images. We are seeing back in time, not at space as it is at the moment.
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