Please excuse the following smarty-pants rant.
When I read the article, Astronomers To Gaze Back In Time And Map History Of Universe, I thought, Nope, that’s bullshit, can’t do it.
The physics and philosophy of time is perhaps my greatest interest, so I read the article with interest and care.
Here is what the researchers aim to do -
Making use of an Infrared Array Camera on NASA’s Spitzer Space Telescope, the Spitzer Extragalactic Representative Volume Survey (SERVS) will make a very large map of the sky, capable of detecting extremely faint galaxies. The primary aim is to chart the distribution of stars and black holes from when the Universe was less than a billion years old to the present day.
And the goal?
[to] detect moderately massive galaxies when the Universe was less than 8% of its current age.
Can we call that “gazing back in time?” Strictly speaking, no. As Einstein taught us, there is no ultimate reference frame, a perfect and final x,y,z & t. Instead, there are multitudes of reference frames out there, each equally valid. Einstein further blew minds by demonstrating that time can “flow” at different rates in different frames. There is no single “time” in the universe, there are “times.”
Also thanks to Einstein and the work of other physicists and philosophers, we understand that information is not transmitted instantaneously. At its fastest, information travels at the speed of light. So a person on planet 1 may learn about planet 2 exploding before or after a person on planet 3. In a real sense, looking “back in time” involves receiving information, in our reference frame, that we know took a long time to get here. Rather than looking back in our own time, we are gazing at old information from another time. No clock is sent spinning backwards.
Another analogy: Say you receive a mangled Christmas card your now deceased grandmother sent you five years ago (and apparently got lost somewhere in a postal warehouse). By reading it, are you gazing back in time? Maybe your imagination is. But the card is right there in your own time.
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