Archive for the ‘Dispatch’ Category

h1

Dispatch: Eridian Birthday

January 6, 2009

erisdysThis is a Hubble Space Telescope image of the 9th largest known object in our solar system (besides the sun), and its moon.

Pluto, right?

Pluto, wrong.

It’s Eris, the largest dwarf planet, and Dysnomia, its moon.

I tell visitors that this is one of the reasons that “dwarf planets” as a new classification of planets was introduced–there are objects in our solar system that are bigger than Pluto.  Should that make them a planet?

Here’s a typical exchange that occurs when someone brings up Pluto/Dwarf Planets:

Me: Is Pluto a planet?

School Kids: No!

Me: What makes something a planet?

School Kids: It’s made of dirt!

Me: Ok, dirt– like it has a ground you can stand on.  But how about Jupiter, and the rest of the outer planets?  Do they have a ground?

School Kids: No?

Me: That’s right, they don’t.  They’re made of gas, that’s why they’re called “gas giants.”  So a planet doesn’t need ground.  If not, what exactly makes something a planet?

School Kids: It has to be round!

Me: Round like a circle?

School Kids: No, round like a ball, smart arse.

Me: Ah, then we call that “spherical.”  Ok, well, the Sun is spherical.  Does that make it a planet?

School Kids: Of course not, don’t be silly.

Me: So what makes something a planet?

School Kids: It has to orbit the Sun.

Me: But asteroids and comets orbit the sun, does that make them planets?

School Kids: No, it has to orbit the sun and be big.

Me: Bigger than Pluto.

School Kids: Yes, jeez!

Me: So our moon is a planet then, because it’s bigger than Pluto and orbits the sun.  Right?

School Kids: Uh… No?

Me: You’re right, the Moon is a moon, a satellite.  And it’s good that’s not the deciding factor, because there are seven moons in our solar system that are larger than Pluto: Ganymede, Titan, Callisto, Io, the Moon, Europa, and Triton.  So if they’re not planets, then what makes something a planet?

School Kids: Uh…  Just where are you going with this, wise guy?

Me: There are a handful of technical definitions for what makes something a planet or not, but to be perfectly honest, the only way to know for sure if something is a planet or not–a bunch of people get together and vote.

School Kids: Say what now?

Me: It’s true, the International Astronomical Union governs the naming conventions for astronomical bodies.

School Kids: So some dudes get to decide if something’s a planet or not?

Me: Dudes and ladies.  Pretty much, yeah.

School Kids: Far out, man.

Me: Word.

Ok, maybe that’s not verbatim, but fairly you get the idea.

Ultimately, the confusion surrounding the classifications of these things (dwarf planets, plutoids, TNOs, etc.) is just semantics: the words describing them don’t actually change what they are: small objects in the outer edges of the solar system.

Anyway, I digress.  A trio of astronomers scouring the sky for Trans-Neptunian Objects found Eris on January 5 of 2005, after studying photos taken in 2003.  (The sky is a big place to observe; often discoveries are made long after initial images are taken, because there’s just so much darn data to look at.)

The namesake of this dwarf planet is the Roman goddess of strife and discord, an appropriate association since Eris was one of the reasons the IAU decided to start thinking about new solar system classifications, an act that has led to a considerable strife and discord over the demotion of Pluto.

Astronomers love relating names like this, and Dysnomia is another perfect example.  Follow this train of geek-thought:

Eris was informally nicknamed Xena by the discovery team, and naturally Xena’s moon should be Gabrielle.  The meaning of “dysnomia” translates to “lawlessness” in English–And the character of Xena was played by actress Lucy Lawless.

And yes, that was totally on purpose.

I did make the mistake (once) of trying to explain this connection to a school group of 3rd graders in my theater.  Of course the teachers knew who I was talking about, but the kids had no clue.

I was half tempted to say, “You know, that amazonian lesbian couple from the syndicated psuedo-Roman TV show in the mid-90s…” but fortunately kept my mouth shut.

h1

Dispatch: Moonwalker

November 11, 2008

The Soviet Union was the first space program (like one or two other very important milestones in aerospace history) to put a remote-controlled robotic vehicle on another world.

lunokhod_1

In Soviet Russia, moon walks on you!

It’s name was Lunokhod 1 (literally, moon walker) and if you didn’t know better, you might think it was some sort of fictional steampunk kitbash.

Just look at this monster.  It was 2.3 meters long (seven and a half-ish feet!), and I haven’t been able to find its weight anywhere, but it must have been pretty hefty.

Overall, the rover itself was pretty straightforward.  The tub-like body was a sealed chamber filled with nitrogen and temperature regulated by Polonium-210, and was covered by a hinged lid.  The chassis had eight independently-powered wheels (plus another roller at its rear which acted as an odometer).

It had a slew of simple testing devices, including cameras, geology tools, a spectrometer, a small x-ray telescope, and a laser.  Two antennas relayed its data back to Earth, one a vertical conical visible in the above photo, the other a super-directional helical antenna (the upper boom sticking out at an angle).  The flipped-open device at the front is a laser retroreflector.

The whole shebang was powered by batteries which were recharged throughout the lunar day by a bank of solar cells underneath the main body’s lid, which would flip open to soak up some E.

To me, this guy looks pretty much exactly what I imagine a big, rugged, late ’60s Russian lunar robot should look like.

And they built it to last; they expected to get three lunar days of operation out of it (three-ish Earth months… do I really need to do that math for you?) but ended up getting almost eleven lunar days of life, constituting 20000ish video images, over 200 hi-rez pans, 25 spectrographic soil tests, around 500 soil punctures, and about 10 kilometers of travel.

Lunokhod had a sister, Lunokhod 2, which in it’s 4 lunar days of life traveled a nearly unbelievable 37 kilometers.  A third rover was built, but not launched.

I guess you could say that these guys were the great-grandparents of Sojurner, Spirit and Opportunity.  And despite their data being nearly 40 years old, you can bet that the info and pics they radioed back home will still be handy in the future explorations of our planet’s closest astronomical neighbor.

The spacecraft which carried Lunokhod 1 on its voyage was named Luna 17, and was launched on November 10, 1970.  It touched down on the moon’s surface and dropped off its passenger a week later, November 17.

h1

Remember, Remember, the Meteor Fender

November 5, 2008
Not like this.

Not like this.

Imagine that you’re a spacecraft flying through space at up to many dozens of kilometers per second.

Now imagine that a tiny piece of space dust lies directly in your path; it too may be traveling at hypervelocity.  Even if you could see it, it’s difficult to swerve in space.

Even an extremely small piece of space detritus (micrometeoroids, a tiny chunk of comet, heck, even possibly human-made objects) can cause a catastrophic impact to a vehicle with very delicate components, due to very high relative speeds.

Read the rest of this entry ?