People are saying that The Pillars Of Creation have been destroyed, and will take 400-500 Million light years to reach us. Can someone explain how do we know it when the light hasn’t reached us?
In: 1444
The pillars of creation are 400 – 500 million light years away. This isn’t a time, this is a distance. It takes light 400 – 500 million years to get from there to here.
That means what we’re seeing when we look at the pillars of creation is actually what it looked like 400 – 500 million years ago. Something like that is probably deformed, destroyed, or some other way non-existent anymore in this current moment, but because the light takes so long to reach us, we can still see it existing.
When you look at stuff this far away, it’s like you’re time travelling in the past because of the time it takes light to get from what you’re looking at to your eyes.
Strictly speaking we can’t know for sure. We can look at what was going on 6500 years ago (when the light that we see now was first emitted and/or reflected from the objects), and we can make some educated guesses as to what has *probably* happened since then, given what we know about astronomy. According to our current theories, the Pillars “should” be gone by now: it’s not so much that they’ve been destroyed as that they’re in a transitional phase as one type of matter turns into another, and that process is likely to continue.
That said, 6500 years is a long time. It is possible something happened that we can’t currently anticipate. It’s also possible that there’s an error in our theories about how a structure like this would evolve over time. But if we assume neither of these is the case, then at least to the best of our current knowledge, the structure we now call the Pillars of Creation is *probably* gone, or at least changed into a form that we wouldn’t recognize as being the same thing.
That light done passed us by already millions of years ago. We’re just traveling towards a black hole. In universe time, that’s why we dont notice.
How close would you need to be to see the pillars in all their glory with the naked eye? Is it even possible?
“Lightyear” is a unit of distance not time, and the Pillars of Creation are only around 7,000 lightyears from Earth.
The reason we think they may no longest exist is that we have observed what is potentially a supernova shockwave in the Pillars which, as the pillars are essentially giant clouds of gas and dust, would have literally “blown them away” within 1,000-2,000 years. Since the light from the Pillars takes around 7,000 years to reach us we will be able to observe them for around 5,000-6,000 more years. But we’re not sure if it’s a supernova, and if it isn’t then the Pillars should continue to exist for a much longer time.
A light-year is a measure of distance, isn’t it? The distance traveled by light in a year?
If someone throws a baseball at your head, even though it hasn’t hit your head yet you know it’s going to.
It’s a bit pop-science to say things like this.
The speed of light is what it is because that’s how fast causality itself can propagate information across the unbroken fabric of space.
So it’s cause and effect that moves at the speed of light, and light just happens to be the only thing that can ride that limit.
We can make predictions of course, but how we’re seeing the Pillars now is how they “really are” to us in any meaningful sense.
If we could see that, then aren’t we seeing into the future? I always thought of the speed of light as being more akin to the speed of causality
We don’t know it. It’s partly why the commonly repeated phrase “…the light from this thing has travelled millions of years to reach us” is problematic. There is no cosmic clock. All information travels at the speed of light. So for all intents and purposes, the pillars of creation are still there until we don’t see them anymore. In fact their gravitational effect on us is also just now reaching us.
Another example. If the sun disappeared “right now” we would continue to orbit it. And see it, and sunbathe in it. 8 minutes later the lights would go out. But what does it mean to say that happened in the past? what past? It happens IMO when the light and gravity change reaches you.
of course if someone discovers FTL travel then i’m wrong.
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