How cool is it that we now have an actual image of the event horizon of a black hole! More precisely: it’s the glowing accretion disc of matter falling into the black hole, and the event horizon’s silhouette.
The Event Horizon Telescope, actually a worldwide array of telescopes, used interferometry to effectively create a planet-sized telescope to see the light around the supermassive black hole at the center of M87, a galaxy 55 million light years away.
I remember talking with a college classmate about giant interferometry telescopes back in the late 1990s. It’s incredible to see the technique actually making discoveries like this!
What we’re seeing in this image isn’t a top-down view of the accretion disc, but an angled one — think of Saturn’s rings — and the gravity of the black hole is bending the light from the disc.
Phil Plait has a great article on the science behind the image. @AstroKatie has a Twitter thread on how the image was produced, why the ring looks the way it does (it tells us which direction the disc is spinning!), plus simulations of this type of black hole seen from different viewing angles.
Direct links to the articles she mentions:
And this Mastodon thread by @SohKamYung@mstdn.io collects some more articles worth checking out:
Forbes makes the excellent point that, while we’d seen a lot of circumstantial evidence for black holes over the last few decades, this confirms that they exist.
The evening was hectic, and I almost forgot. I had literally just put my son to bed when I remembered, “The eclipse!” We went out to see if the sky was clear.
Clouds were rushing across the sky, but for the most part, it was clear, and we had a perfect view of the moon looking like a dark brown chunk of rock in the sky.
(Then I spent 10 minutes fighting with camera settings while he went back to bed.)
Update: I went back out about an hour later to check out the view as the moon left the earth’s shadow, and caught these two photos, taken about the same time with different exposures so that you can see either the lit portion of the moon, or the part that’s still in the earth’s shadow.
I woke up way too early to see if the Super Blue Blood Moon* eclipse would be visible or blocked by clouds. (You never know, and I didn’t want to wake up the kiddo in the middle of a school night if there wasn’t anything to see.) I had a clear view, but the street lights were too bright to see the red color. It just looked dull brown.
So I took a couple of pictures, then went back in to wake up the kid. He still wanted to go out and see, but only for one look. Totally understandable. I carried him out, we looked at the darkened moon, then I carried him back in and put him back to bed.
It’s the third lunar eclipse he’s seen, though one of them we didn’t get to see much of since it was so cloudy. And while it’s not as cool as a total solar eclipse, it’s something you can see with no special equipment by walking out into your front yard anywhere in the world that has a view of the moon during the several hours it takes the Earth’s shadow to move across it.
I went back out one last time to try for some photos of totality, but they didn’t come out any better than the ones I took the first time. I looked around for a spot that might be darker and still have a view of the moon (without trespassing in someone else’s back yard), but didn’t see one — there are way too many lights at night these days. Then I tried to place the constellations I could see, and failed. Then I went back in to go back to bed.
Unfortunately I don’t think I really got back to sleep, so I’ve been dragging all morning. The interruption didn’t help the kiddo either, so getting him to school was a bit of a challenge.
*Blood moon: lunar eclipse, Earth’s shadow darkening the moon & turning it red. Cool to see, widely visible.
Super moon: full moon during closest point in orbit, looks slightly bigger.
Blue moon: 2nd full moon in a calendar month, otherwise no difference.
Yesterday’s Falcon 9 rocket launch from Vandenberg AFB, seen across Southern California.
I walked outside and saw a bright spot (presumably the rocket) moving across the sky, trailing an expanding shell of vapor.
I ran back inside shouting “come see this, fast!” and grabbed the better camera, but it wouldn’t focus, so I snapped the top photo with my phone.
The yellow light is a street lamp. The upper bright spot is the moon. I believe the lower left is the rocket, and the lower right is the booster stage. A ring of light pulsed outward from the booster stage at one point.
The vapor trail persisted for another 10 minutes after the rocket and booster were no longer visible, and it was high enough to continue reflecting sunlight, even though it was an hour past sunset.
I’ve always wanted to see a total solar eclipse, but until now I never had the opportunity. I’ve caught a number of partial solar eclipses over the years, and quite a few lunar eclipses. This year’s “Great American Eclipse” was perfect: it passed close to Portland, where we have family, and we could visit friends on the way up.
By the time I reserved our hotel there was nothing left inside the path of totality, but we could still get an expensive room in Portland. I reserved that immediately for the nights before and after, then a motel for a few nights before so we would have time to visit, then we planned out the trip up and back.
Driving Into the Path
The morning of August 21, we got up at 5:30 to drive south into the path of the eclipse. We didn’t actually make it out the door until at least 6:30, and the parking attendant had lost our key (fortunately we had two, and they did eventually find it that afternoon), and then we got lost trying to find an ATM in case we had to pay a ton to park in someone’s field (one way streets and bridges and driving into the early morning sun), but we got on the road toward Salem by around 7:15/7:30, with our eclipse glasses, water, snacks/emergency food, and a very sleepy 6½ year old.
The threatened traffic jam carpocalypse didn’t materialize. There were slowdowns, sure, but nothing we hadn’t experienced on the way out of LA. Our nav system (which J. calls the “map lady”) sent us onto a side road at one point, and we drove through the countryside a while before getting back onto the interstate.