Tag: astronomy

Optical Discs

Posted on by Brian Garthwaite
Stack of DVD-R discs.
Never used, never to be used.

It really wasn’t that long ago that computers came equipped with optical disc drives, and they were effective means of data storage, and the density you could store on a DVD instead of a CD was pretty exciting. Now? They’re not only borderline-useless, but the features that we used to reference as a cultural touchstone are no longer obvious to our students.

It’s not that they don’t know what these are. It’s that they haven’t handled a million of them to know their dimensions, to understand the diffraction rainbow they make. The physicists around here remember using the inescapable AOL discs as cheap, readily available diffraction gratings back in grad school. The astronomers use their proportions to illustrate the shape of the Milky Way Galaxy. Students now need to physically hold one of these to get the idea, because they don’t have a mental image ready to go.

Our Galaxy, if you were wondering, is roughly proportioned as a CD, only instead of being a millimeter and a half thick, is more like 1,000 light years. Very roughly, anyway.

Apollo 13

Posted on by Brian Garthwaite
News release announcing the upcoming Apollo 11 launch in 1970.
We all saw the movie, right?

Fifty-five years ago saw the launch of the Apollo 13 lunar mission, on 11 April 1970. It didn’t go to plan, of course. Things took a bad turn, could have been worse, but who can blame them for optimism in the weeks leading up to it all? Moon science is cool!

Check out that pure 1970 map illustration!

Maps, plans, a pretty tight itinerary. It’s expensive and difficult to go to the Moon, so you don’t waste time. But don’t those hand-drawn maps just make it so inviting? Presumably the astronauts carried maps which were much more detailed and useful, if less likely to get the kid inside all of us super-excited.

Apollo 14 would reach the Fra Mauro highlands in early 1971, though Lovell, Swigert, and Haise never flew into space again.

Stamped

Posted on by Brian Garthwaite
Lead brick, painted yellow, stamped by Nuclear Associates of Carle Place, NY.
It’s big, heavy, and boldly colored.

Lead bricks are useful things. This one – still bearing the stamp of Nuclear Associates, of Carle Place, NY – has had its fair share of scuffs and dents. (Lead’s soft stuff, you know.) These days it functions as a handy doorstop and a hands-on tool for explaining the density of matter.

Denser than water, than aluminum, than a nickel-iron meteorite. (All easy samples to acquire for demonstration.) Less dense than osmium; about half as much. (Not on hand, unfortunately.) Definitely less dense than the core of our Sun, by an order of magnitude-plus.

Also no handy samples of stellar core plasma on hand.

Leonids

Posted on by Brian Garthwaite
Meteor counting log, Leonids shower, from November 1934
Up to three per minute!

Ninety years ago, during the Leonids meteor shower, someone was counting a lot of burning bits of debris from comet 55P/Tempel-Tuttle. With one fifteen-minute window boasting forty-five meteors (!), that’s a powerfully active shower. Not quite a storm, but those happen with the Leonids sometimes.

According to NASA, the Leonids peak about every 33 years, with 1966 being a spectacular meteor storm. In one fifteen-minute window, thousands of meteors fell like glowing rain. How amazing is that?

Also: check out the times indicated. We’re assuming the counting started at 11:00pm and ran until early morning, with a 24-hour clock opposite how we’d expect it. (Maybe sleep deprivation?) Either that or it was a truly spectacular meteor shower!

Battery Access

Posted on by Brian Garthwaite
Temperature probe, open case, with circuit board, batteries, and screwdriver.
Always entertaining: the original, off-brand battery.

When the screw heads to the battery access panel are stripped, just go all the way and open up the entire housing. Why not?

The real question is this: why are those screws stripped? Did it arrive that way, battery installed, or did they take a real beating after popping the first battery in? Why have screws to keep it shut in the first place?

Metersticks

Posted on by Brian Garthwaite
Three metersticks
Various vintages.

In our Physics & Astronomy labs, we use metersticks with great frequency. Often for measurements, sometimes to approximate distances that make the arithmetic easier, and occasionally as a handy tool for pointing to the projector screen.

They aren’t super-high precision any more than the rulers you remember from elementary school, and for that we have other tools. Sometimes, as you can see above, the years have warped and twisted things a bit. We adjust.

As you might expect, they offer metric distances on one side, inches and feet on the other. The best ones – the oldest set – were long ago painted black to conceal those SAE units. Clearly, someone grew weary of students measuring everything in inches and then complaining that the math wasn’t working out right.