Something odd happens when we consider scales much larger or smaller than our ordinary experience; our imagination fails.
It's why people seem not to comprehend the difference between millionaires and billionaires. Millionaires are wealthy, yes. But billionaires?
If a person with a billion dollars gave away a million dollars a day, 365 days a year -- in other words, creating one new millionaire every day -- (s)he wouldn't run out for almost three years. The fact that people lump together millionaires and billionaires as both simply "rich" indicates we don't have a good way to conceptualize how big a billion actually is.
The same thing happens when you look at anything that's very small. In my biology classes, we did a lab where students learned how to estimate measurements using a microscope. Knowing the magnification and the field diameter (the actual width of the bit of the slide you're looking at), it's a fairly simple calculation to estimate the size of (for example) a cell.
What I found the most interesting was that after performing the calculation, most students had no clue whether the answer they'd come up with was even within the ballpark. Most of the time, if they did make an error, it was a simple computational goof; but the curious thing was that they couldn't tell if they were even in the right realm. 0.001 meters? 0.000001 meters? 0.000000000001 meters? All looks pretty similar -- "small."
(Then there's the student who multiplied when she should have divided, and told me that a plant cell was 103 meters in diameter. "Don't you think that's a bit... on the large size?" I asked her. She responded, "Is it?" I told her 103 meters was a little longer than a typical football field. She responded, "Oh.")
This problem crops up in fields like subatomic physics (on one end) and, germane to today's topic, astrophysics (on the other). What got me thinking about it was a paper this week in the journal Astronomy and Astrophysics about a distant quasar with the euphonious name VIK J2348-3054. Quasars are extraordinarily luminous objects which were a puzzle for a long time -- viewed through earthly telescopes they appear as single dim, star-like spots, but based on their redshifts they are enormously far away (and thus, even to be visible at all from that distance their actual luminosity has to be crazy high). The current models support quasars as being supermassive black holes at the centers of young galaxies, emitting high-energy radiation and particles as they swallow vast amounts of gas and dust in a wildly spinning whirlpool called an accretion disk.
An energy output that high causes disruption in the entire region surrounding it. It heats and/or blows away gas and dust nearby, which overcomes the gravitational collapse of clumps of material and thus suppresses star formation. And this quasar is so powerful it has stopped the formation of new stars in a region with a radius of over sixteen million light years.
Stop and ponder that for a moment.
Sixteen million light years isn't just big, it's abso-fucking-lutely enormous. It's six times the distance between the Milky Way and the Andromeda Galaxy. Put into units that more of us are comfortable with, this is about 160,000,000,000,000,000,000 kilometers.
Of course, I'm not sure how much even that helps. Once again, our imaginations simply fail us. Perhaps this will frame it better; the fastest human-made vehicle, Voyager 1, is traveling at about 61,000 kilometers per hour. At this rate, Voyager 1 will have covered one light year in about eighteen thousand years. And that's not even the distance to the nearest star, Proxima Centauri (if it was heading that direction, which it's not).
To travel the distance that has been cleared by this quasar, Voyager 1 would take a bit less than three hundred billion years -- about twenty times the age of the universe.
I don't even know how to wrap my brain around a number this big. I may not have the difficulty with numbers my long-ago student had with her football-field-sized plant cell, but I have sat here all morning trying to understand what it means for something to work over this kind of size range, and I just can't manage it.
The inevitable result is that this kind of thing makes us feel pretty small. I'm actually okay with that. The universe is a grand, beautiful, and abso-fucking-lutely enormous place. It's a good thing to look up into the night sky and feel awe, to realize that every star you see is (relatively speaking) close by, occupying a small spherical region in one arm of a completely ordinary galaxy, of which there are millions more scattered across the vastness of space.
We humans get a little big for our britches, sometimes. A dose of humility is needed every so often.
And if it comes from the realm of science, so much the better.
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