Asteroids used to be called “the vermin of the sky”, because as they orbit the Sun they move right across some more “interesting’ target astronomers were trying to photograph, like a nebula or galaxy, leaving time-exposure streaks behind that ruined the observation.

But of course nowadays asteroids are a field of study in their own right, and a very interesting one. What used to be an irritation is now an advantage: we have so many telescopes observing the sky that asteroids passing through the field of view become targets of science.

Hubble gets great images of asteroids, and a lot of data can be squeezed out of those observations. Looking at a staggering 37,000 Hubble images (!!!) over 19 years, scientists found 178 previously known objects and 454 previously unknown ones. As they move they leave trails in the image, like in this fabulous shot of the galaxy UGC 12158, a spiral about 400 million light-years from Earth:

As Hubble orbits the Earth, the angle at which it sees an asteroid changes a tiny bit, causing the asteroid track to curve. The amount of curvature due to this parallax can then be used to get the distance to an asteroid! With ground-based telescopes this usually requires observations over several nights, during which the asteroid’s orbital motion can be used to determine its orbital shape and distance.

Because Hubble points somewhat randomly in the sky, the collection of asteroid trails provides a statistically significant sample. Not only that but Hubble is so sensitive that it sees much fainter asteroids in those short times than is possible from the ground. Interestingly, they found more faint objects than you’d naively expect from previous observations, something hinted at but not seen clearly before.

This is likely due to smaller asteroids being fragments of bigger ones blasted off during collisions. We know this happens, but seeing these much fainter smaller pieces appears to support the idea. The observations also show in general that Hubble can be used to probe this regime of the solar system. The observatory wasn’t really designed to do this, but this is what you get when you build a fantastically sensitive machine that looks all over the sky, and the images become public. In fact, the scientists relied on citizen scientists —people who are not professional scientists, just interested laypeople — using the (now completed) Hubble Asteroid Hunter project to identify the asteroids! [link to journal paper]

This is a great example of the professional-amateur collaboration, doing real science and expanding the frontiers of understanding. I strongly support this effort.

My friend and climate scientist Katharine Hayhoe posted an interesting and hopeful graph on Bluesky, showing energy production sources in Colorado in 2001 versus 2023 (the source is The Colorado Sun on Threads, using data from the US government’s Energy Information Administration).

In 2001 coal and methane* together made up a staggering 97% of energy production. Just two decades later they dropped to 63%. Solar and wind were negligible, less than 1% in 2001, but are now 34%, over a third of all energy produced! I’ll add that the growth of renewables like solar and wind is accelerating, so a lot of that ground was gained more recently, making the situation even better than implied here.

Solar in particular is growing rapidly thanks to panel production costs dropping like a stone. I like it for that reason, plus I think more energy production should be hyperlocal, made on the spot where it’s needed like homes and buildings. It’s cheaper and easier — piping electricity long distances is more expensive and a lot is lost along the way due to inefficiencies in the process. Hyperlocal production means you’re also less susceptible to power loss due to weather. We had panels and batteries on our house in Colorado and never lost power for more than a moment. We lived on the end of a dirt road and power went out frequently for our neighbors, but we were fine.

I’ll add that a big solar storm can cause widespread and long-lasting blackouts. They are unlikely at any given time, but over decades the chances of a big event rise to a certainty. We should be preparing for that, especially since it’s the right thing to do anyway!

We’re looking into solar for our house in Virginia, but we’re in a forest and shadowing is an issue. Cost too, of course: in the long run it saves a lot of money, but there is an initial outlay we’d need to pay for, so in all honesty we may have to wait a while. But we hope to switch eventually.

I’ll add that the biggest contributors to global warming are still fossil fuel companies, and they absolutely should be brought to justice for this, and we need to wean ourselves from them. These companies also funded a big disinformation campaign to make you personally feel responsible for global warming and climate change, to take the heat — so to speak — off themselves. But that’s baloney, and you shouldn’t fret too much over your own footprint.

Still, individual efforts can make a big difference if enough people undertake them. Using more solar and wind is a great way to do this. Look into it if you can.

* The common term for this is “natural gas”, and this is what we call greenwashing, making something seem environmentally friendly when it very much is not. Natural gas is almost entirely methane, which is a stronger greenhouse gas than carbon dioxide (it doesn’t last long in the atmosphere, but breaks down into water and carbon dioxide, so it’s still awful for global warming either way). This is why I don’t use the term anymore. 

You can email me at [email protected] (though replies can take a while), and all my social media outlets are gathered together at about.me. Also, if you don’t already, please subscribe to this newsletter! And feel free to tell a friend or nine, too. Thanks!