BAN #93: A young cosmic bauble, a dragon in the shadows
March 4, 2019 Issue #93
|Phil Plait||Mar 4, 2019|| 1|
Subscribers feel 200 million years younger!
Pic o’ the Letter
A cool or lovely or mind-bending astronomical image/video with a short description so you can grok it
I was poking around my notes over the weekend, looking for something to write about for the newsletter — whenever I see something online I might be able to use here or for the blog, I cut-n-paste the URL into a doc and save it to my desktop, titled provocatively for later self-attention-getting. I found a file I saved a couple of weeks ago with the title “Globulars”, and knew I had a winner.
What’s a globular, you ask? Why, this:
[Credit: ESA/Hubble and NASA]
Yeah, I know, right?
That’s NGC 1866, a cluster of a hundred thousand or so stars all orbiting around their common center of gravity. That’s a Hubble image of it, and usually a typical globular will fill the field of view. However, this one is pretty far away, so it appears smaller. And by far I mean it; a typical globular might be 10 – 20,000 light years from Earth. NGC 1866 is about 170,000!
It’s actually part of the Large Magellanic Cloud (LMC) a satellite galaxy to the Milky Way. It’s not like globulars we see orbiting our galaxy. Most of ours have stars that are all the same age, indicating they all formed at the same time. Globulars tend to be very old, as old or maybe even older than the galaxy, 10 – 12 billion years of age. They were some of the first objects to form in the Universe!
NGC 1866 is different, though. Really different. Analysis of the stars indicate it’s only about 200 million years old! That’s really young. Moreover, there appears to be at least two different populations of stars in it, with some around 200 million years old, and another that span 140 – 220 million.
The LMC is lousy with gas, the building blocks of stars. It’s possible close passes to the LMC drove star formation in NGC 1866, creating the two populations. Interestingly, there’s a vast star-forming complex in the LMC called the Tarantula Nebula that’s making stars so vigorously it may be birthing a globular cluster! So it’s likely the young age of NGC 1866 is because it formed in the LMC.
[The Tarantula Nebula, c/o the Very Large Telescope Survey Telescope. Credit: ESO]
Either way, it’s gorgeous isn’t it? I love globulars, which is why I write about them so often. Funny, too: In that doc I saved with this image, there was a link to a Hubble image of another LMC globular, too. I actually started writing about that one, and before I knew it it blew up into 1100 words! So I decided to use that for the blog, and write about this one for the newsletter, where I think shorter articles are better.
There was a third link there, too, about some new globulars just discovered… but I think that deserves its own article as well.
I know some writers worry about writer’s block, but to be honest it’s never been a problem for me with the blog. There’s too much to write about! All it takes is a Hubble image of some glittering bauble and the words aren’t too hard to find. I’m very, very lucky to be in this position. I love my job, and it’s honestly fun to do.
Space is big. That’s why we call it “space”
You probably heard that SpaceX successfully launched a crew-ready Dragon capsule to the International Space Station on Saturday, and just a day later it docked itself. The astronauts from ISS have been having fun inside it, and have unloaded the 200 kg of supplies.
You can find tons of info about this online, but I just wanted to show you this truly stunning photo taken by one of the astronauts:
With the Sun on the horizon from this angle, our entire ocean of air is a thin blue crescent, with just a sliver of it and the Sun stained red by atmospheric scattering. Now look to the right of the Sun. See it there? That’s the silhouette of the Crew Dragon on approach.
Sometime in the next few weeks/months SpaceX will do a critical in-flight abort test of the capsule, and if that goes well, there may be living breathing human beings on board that shadowed spaceship the next time you see a photo like this.
What I’ve recently written on the blog, ICYMI
[2014 MU69 as seen by the New Horizons spacecraft. See Tuesday’s post below. Credit: NASA/Johns Hopkins Applied Physics Laboratory/Southwest Research Institute, National Optical Astronomy Observatory]
Monday Feb. 25, 2019: Does Planet 9 Exist? <All signs (still) point to 'yes'>
Tuesday Feb. 26, 2019: Here it is: The most detailed full image of MU69 from New Horizons we'll ever see.
Wednesday Feb. 27, 2019: Sometime in the past decade Mars suffered an impact shotgun blast
Thursday Feb. 28, 2019: An epically erupting star has carved a truly GIGANTIC hole in space
Friday March 1, 2019: Tonight SpaceX takes the next big step in returning Americans to space
You can email me at email@example.com (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!