Thursday Throughput 2/28

[ThTh1] So today is February 28. Since it’s 2019, there will be no leap year. So those of you still on the Julian Calendar will not be falling any further behind. Hope you had a good Valentine’s Day yesterday. Next year, I’ll go into some detail on leap years. And maybe leap seconds. In the meantime, I’ll note that the common conception that February has only 28 days because Augustus stole a couple of days is … a myth.

[ThTh2] I mentioned in this space before that the Opportunity rover has stopped talking. NASA officially pulled the plug. The oft-repeated meme that Opportunity’s last message was “it’s getting dark and my batteries are low” is not literally true but is an accurate figurative representation of the last data it sent back.

[ThTh3] One of the big questions in planetary astronomy is whether there a ninth planet or not. No, I’m not referring to Pluto’s status. I’m referring to the possibility of a much larger body out in the Kuiper Belt. There is an intense debate raging about whether the orbits of trans-Neptunian objects require a large planet or not. Until we detect one, that debate will continue. In the meantime, enjoy the Planetary Society’s montage of things that aren’t planets:

Montage by Emily Lakdawalla. The Moon: Gari Arrillaga. Other data: NASA/JPL/JHUAPL/SwRI/UCLA/MPS/IDA. Processing by Ted Stryk, Gordan Ugarkovic, Emily Lakdawalla, and Jason Perry.

[ThTh4] The War on Cervical Cancer continues to progress. Not only do we have a vaccine, we may now have a cure.

[ThTh5] One of the tactics of interplanetary war that shows up in science fiction from to time is the idea of dropping objects on a planet from space. In particular, the idea of dropping a rod — which minimizes the cross-section for air resistance — has shown up in various stories. Turns out, the Air Force was paying attention.

[ThTh6] In 1974, scientists at the Arecibo Radio Telescope in Puerto Rico broadcast a message to a distant globular cluster. They now want to broadcast a second and are enlisting kids to try to figure out what message to send. I link the article not just for that but for the ongoing debate about whether we should be broadcasting our presence at all lest we invite a hostile response.

[ThTh7] I’ve mentioned Oumuamua, the extrasolar comet, a few times. I had planned a post on alternative to the idea, advanced by Avi Loeb, that this was an alien solar sail. But now there are three theories, all of which are reasonable. The simple fact is that we’re in unexplored territory here. We’ve never seen an object like this. And unless we see another one, we won’t really be able to know for certain what it was.

[ThTh8] I love this video, showing an entire day at the South Pole and other low-latitude sites. A textbook case of how the Sun’s motion changes depending on where you are on Earth.

Looping 24hr 180 degree fisheye time-lapse footage, shot with the camera pointing straight up at the South Pole, Scott Base, and Christchurch NZ in summer. Noon is when the sun is at the bottom of the each picture.#Antarctica #astronomy #astrophotography #timelapse #education pic.twitter.com/q3fklWnIpl

— Anthony Powell (@Antzkiwi) February 22, 2019

[ThTh9] One of the more frustrating things for scientists to deal with is a lack of understanding of how probability works. Just because something has a one-in-four chance of happening does not mean it happens exactly one-in-four times. Nor does it mean it can’t happen at all. Here’s a lovely video demonstrating this:

This is an elegant video of how probability and sampling works – larger samples provide more accurate estimates of the underlying probabilities.

(via https://t.co/5LpIBI8Ygu)https://t.co/WLJTMxpt5O pic.twitter.com/20iAp2KUWI

— Jay Van Bavel (@jayvanbavel) February 25, 2019

[ThTh10] How big is Earth’s atmosphere? Depends kind of on how you to define it. But it probably extends past the moon.

[ThTh11] Radiation tends to scare people. We heard a couple of weeks ago that some radioactive uranium ore had been found in the Grand Canyon museum, potentially exposing tourists to dangerous levels of radiation. But … we can take a deep breath. No, the shouldn’t have been there, but the actual risk appears to have been minimal. I mean … minimal for uranium.