If dark matter is fully explained by such black holes, their most likely mass, according to some theories, would range from 10^17^ to 10^23^ grams—or about that of a large asteroid.
In case this doesn’t tell you a lot, 10^17^g is half the weight of Mount Everest, and 10^23^g is 4x the weight of the Antarctic ice shield.
The earth is estimated to “weigh” 13,170,000,000,000,000,000,000,000 pounds. (That is weird when you think about it. The weight of the earth being based on what something weighs on earth, I mean.)
Mt. Everest is only about 357,000,000,000,000 pounds and is just a tiny fraction of the mass of the earth.
So. My point is that we need a better way to portray scale of things in the universe. AUs work to a point but then we have to quickly move to parsecs. Parsecs quickly give way to light years. (Or vice-versa, depending on how you visualize things better.) Light years kinda work, but only for between 14-26 billion years. Even after all of that, I can hardly still fathom the size of Mt. Everest. (This was a rant, but not an angry rant.)
Weight in pounds isn’t the right unit here. Weight varies depending on the strength of the gravitational field you’re in, whereas mass does not. A kilogram here on earth weighs 2.2lbs but on the moon it only weighs 0.36lbs.
In the English Engineering System, the unit of mass is 1 pound mass (lbm), and is equivalent to the amount of matter that weighs 1lb at 1G. I won’t argue that EES is a good system, but it does at least have a kludged unit for mass. It has an equally kludged unit for force, too, called pounds force (lbf).
I cannot fathom the size of anything on an astronomical scale. I have seen the videos that zoom out and show Earth at scale with the Sun and then the Sun at scale with other stars. No matter how many times I view the facts it will be incomprehensibly large.
It’s a worth pointing out that pounds (lbs) is a measurement of mass, not weight, and is therefore not determined by the gravity acting upon it, or the source of it.
Totally! My favorite astronomical “wow” with my daughter was when she was 12. She wanted to learn about photography, so I set up a tripod at dusk to teach her about aperture, shutter speed, and motion blur. We also compared shots with a remote shutter so she could see how the slightest camera shake during a long exposure would result in a blurry shot.
We were about to go inside once the stars came out, but instead I thought it would be fun to show her how they looked with a two second exposure. “Wait, why do they look like little commas? Are they moving?” I didn’t say a word. I just looked at her, and then it hit…
😳”No! We’re moving!”🤯
Facts aren’t nearly as interesting without the connection of self-discovery.
She came really close to another mind-blowing fact: if you’re talking about linear motion, there’s no difference at all between “they’re moving” and “we’re moving”. Too bad the apparent motion of the stars is caused by rotation, otherwise it would have been a great lesson to introduce basic relativity concepts.
She understood the curved lines as illustrating the rotation of the Earth. We didn’t get into motion away from the universal center.
She’s much older now. Tyson’s version of Cosmos came out in her teens, so we watched all of those and then went back for the OG Sagan episodes. She’s my favorite nerd.
When I was a kid my parents bought me a book called “practical astronomy with your calculator” that went over all the workings and formulae for calculating eclipses, moon phases, locations of the planets and heaps more. If you want to get into it I highly recommend this book or something similar.
Aside from the fact that anything with mass cannot travel at the speed of light… Lots of fun things happen as you approach the speed of light. There’s an excellent mostly-hard sci fi novel called Tau Zero that explores this concept in depth and, despite being older, is worth the read.
(1) Time dilation (the universe and you have different clocks).
(2) blueshifting of objects in front of you. At 0.95c, basically all visible starlight in front of you has been blueshifted into ionizing radiation. Fun fun.
(3) shape distortion. You become more needle-shaped – getting very long and skinny, as observed by the rest of the universe.
(4) you become a nuke. At .99c if you run into anything, your kinetic energy related explosion would be roughly 6x the Tsar Bomba (largest nuke ever detonated) for each kg of mass. Or, put another way, each kg of your mass would impact with the energy of 3kg of antimatter contacting 3kg of matter. Boom.
Sci fi always overlooks the last one. Near light speed combat is basically firing buckets of sand at planets and blowing them up.
Speaking of sci fi, Kim Stanley Robinson’s 2312 does a really good job of incorporating the existential dread and lurking horror of weaponized orbital mechanics.
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