“Spacetime” was just one entity to Albert Einstein’s mind.
So, thus entwined in Einstein’s mind, two words are now combined.
How far is LA from my house, when travelling by car?
“Two hours.” “A hundred twenty miles.” Both phrases tell how far.

Spacetime is really something; it can warp and undulate.
What is the spacetime fabric? We are forced to speculate.
It warps around large masses, vibrates when two black holes dance; (1)
Now, this can all be measured; in a huge technical advance.

If spacetime warps and wiggles, then it’s not just nothingless,
For anything that warps and wiggles must be somethingness.
So, when we thought of space as nothing, we made a mistake.
It’s something that can ripple just like water in a lake.

Is spacetime something? What’s that something? Thin, amorphous gruel?
It’s massless with dimensions; when it wiggles, it stays cool.
Because it’s everywhere, it’s also full of lots of things.
If we get all this stuff out, is what’s left some woven strings? (2)

We know it’s all around us but there’s more we need to know.
Since space keeps spouting particles, are they ex nihilo? (3)
How can we do experiments, when we can’t isolate
The stuff we want to study? First, we must depopulate.

Though it takes time to move through space, what are we moving through?
If spacetime’s really unified, we’re moving through time, too.
And, is time made of anything? So far, we’re unaware.
Can time be wiggled, making waves? Or is it simply there?

If spacetime is a fabric, might it rip apart someday?
The cosmos is expanding, stretching faster every day. (4)
And, if the fabric rips apart, what likely happens next?
Nobody has a theory; once more we are perplexed.

(1) Science News, August 12, 2023, p. 12.
(2) Look up “string theory” and see if you can make sense of it.
(3) Can something come from nothing (ex nihilo?) The Romans had a saying, “Ex nihilo nihil fit.” (From nothing, nothing comes,) which they borrowed from the Greek philosopher, Parmenides. Were the ancients right?
(4) There are a couple of independent ways to measure the rate of expansion. They give slightly different answers. Look up the Hubble Constant.