Motion in a straight line

It’s easy to get something to move in a circle; just pin one end down and rotate the rest (like the kind of compass you draw with) or pin the center down and rotate (like a merry-go-round). But how do you get something to move in a perfectly straight line, as is needed, for example, in engines with pistons? I’m reading a delightful book from the 1960’s called “The How and Why of Mechanical Movements,” and the subject of straight-line motion came up in chapter 2 (Levers).

It turns out that a clever arrangement of a collection of rigid bars, connected into a linkage, can give you this magical straight-line motion. Various inspired inventors have come up with different ways to achieve it, and their concepts are illuminating and fascinating.

There’s Watt’s linkage, which requires only three links. It doesn’t quite produce perfectly straight motion (note path of the red point in the animation at right), but good enough that it was used by early steam engines. It’s still used in the rear axle suspension of some vehicles, so that no sideways motion is permitted between the body of the car and the axle (the axle only moves in a vertical straight line with respect to the car body).

The Chebyshev linkage (below left) likewise uses three links and achieves a straighter line, within a prescribed range. In 1864, the Peaucellier-Lipkin linkage (below right) was invented, and it even comes with a proof of collinearity. (These animations are awesome!)

The authors of “How Round is Your Circle?” (another book that looks absolutely engrossing) have an excellent supplementary website. One page shows some beautiful physical incarnations of the almost-straight-line linkages as well as the truly straight-line linkages (check out the videos!).

And now, I’m off to read about more fabulous mechanical movements and be awed by others’ ingenuity.

What causes body aches?

It has always seemed a little unfair that, in the midst of trying to fight off a flu, you would be beset with aches all over your body. What purpose could aching really serve? The only hypothesis I could come up with was that it was a signal from the body to the brain: “Hey, I’m busy fighting a war in here, please divert all possible energy to the production of white blood cells and temperature elevation, and stop trying to walk around.” But once you’re collapsed on the couch, eyes swimming too much even to read, then really, what’s the point in that signaling system continuing its torture?

As usual when googling to learn about any sort of medical symptom, you can find sufficient material to send anyone into a hypochondriac frenzy just based on “body aches.” They could indicate that you are suffering from stress, depression, or even pregnancy! (No, not really. :) )

But back to the why: body aches (myalgia) in the case of the flu are caused by the body’s self-defense functions. According to Richard Deem (Cedars-Sinai Medical Center), macrophages attack diseased cells, producing inflammatory interleukins (especially IL-6, and that inflammation manifests as an aching body. So the aches just mean that the defense system is active—and the bad cells are being weeded out.

Bilingual exoplanet coverage

Others in my French Translation class have chosen works of literature for their translation projects. Me? I chose a recent article announcing a terribly exciting discovery: the first rocky exoplanet! (As opposed to the “hot Jupiters” and other large gaseous planets.) I found this article on the website:

Une première exoplanète rocheuse

Près de 15 ans après la découverte de la première exoplanète en 1995, des astrophysiciens européens ont annoncé avoir trouvé une toute première planète de type rocheuse autour d’une autre étoile que notre Soleil. L’exoplanète Corot 7b avait été observée en début d’année, mais sa composition n’avait pu être établie à ce moment. Sa constitution n’est pas l’unique particularité de Corot 7b. Elle est également la plus petite jamais découverte, avec un rayon équivalent à 1,8 fois celui de la Terre. De plus, c’est la planète la plus proche de son étoile. Elle en fait le tour en seulement 20 heures (correspondant à la durée de son année). Le spectrographe HARPS installé sur le télescope européen de 3,6 mètres de la Silla, au Chili, a également permis d’établir que sa masse correspondait à 4,8 fois celle de la Terre.

Vie impossible
La température dépasse 2000 degrés Celsius sur la face éclairée, puisqu’elle est située à seulement 2,5 millions de kilomètres de son étoile. L’astre pourrait avoir des océans de lave à sa surface. L’autre face, plongée dans la nuit, est glaciale, avec des températures qui plongent sous les -200 degrés Celsius. À titre de comparaison, la Terre tourne à 150 millions de kilomètres du Soleil.

En avril dernier, Gliese 581e avait été présentée comme la plus petite exoplanète. Les découvreurs de Corot 7b estiment que seule la masse de cette dernière est connue, ce qui n’est pas le cas pour Gliese 581e.

Even though my French Translation class is obviously in the humanities, I was a little surprised at some of the students’ reaction to this article — it clearly was perceived as a bit out of place! However, several people commented on how they learned a lot from it: some didn’t even know that we’d discovered exoplanets (!) and others did additional research, reporting (correctly) that we’ve discovered more than 300 of these bodies! So I guess it turned out to be an unexpected chance to sow a little science, and alert others to one of the most amazing advances we’ve made in the last couple of decades (in my humble opinion).

But without further ado, here is my translation:

The first rocky exoplanet

Nearly 15 years after the discovery of the first exoplanet in 1995, European astrophysicists announced that they have found the very first rocky exoplanet around a star other than our Sun. The exoplanet Corot 7b was observed at the beginning of the year, but its composition could not be established until now. Its composition is not Corot 7b’s only distinction. It is also the smallest ever discovered, with a radius equivalent to 1.8 times that of the Earth. Moreover, it is the planet closest to its own star. It orbits in only 20 hours (corresponding to the length of its year). The HARPS spectrograph installed on the 3.6-meter European telescope at La Silla [an observatory], in Chile, has also established that its mass corresponds to 4.8 times that of the Earth.

Life is impossible
Temperatures exceed 2000 degrees Celsius on the illuminated side, since the planet is located only 2.5 million km from its star. The planet* may have oceans of lava on its surface. The other side, plunged into night, is icy, with temperatures that drop to less than -200 degrees Celsius. For comparison, the Earth orbits at 150 million km from the Sun.

Last April, Gliese 581e was presented as the smallest exoplanet. The discoverers of Corot 7b consider mass to be [definitively] known only for Corot 7b, and not for Gliese 581e.

*The word “astre” is translated as “star”, but that makes no sense here; it should be “planet”.

I must say, that final sentence gave me the most trouble! Suggestions about other ways to phrase it are certainly welcome.

In class, we discussed my translation, and I received several suggestions about ways to improve it:

  • “à ce moment” should have been translated as “at that time” rather than “until now.”
  • Consider “duration of its year” rather than “length of its year.”
  • Consider breaking the final sentence of the first paragraph into two sentences, as it is rather unwieldy.
  • Consider changing “The other side, plunged into night” to simply “The dark side” (for clarity over poetry). I disliked “plunged” myself, because it sounds overly dramatic. If wishing to stick closer to the original, someone else suggested “The other side, immersed in night” (less sense of active motion).
  • Apparently “À titre de comparaison” is a stock phrase that means “By way of comparison,” although “For comparison” also works (is probably less formal, though).

After class, I checked how Babelfish and Google Translate rendered this text into English. The Babelfish version is heart-stoppingly bad, beginning with

“Nearly 15 years after the discovery of the first exoplanète in 1995, of the European astrophysicists announced to have found a very first planet of the rock type around d’ another star that our Sun.”

It’s not terrible that Babelfish doesn’t know the word “exoplanète”, but its inability to handle contractions throughout the article is really inexcusable, especially for French! Google Translate’s version is consistently better, but not perfect. The first sentence is rendered:

“Nearly 15 years after the discovery of the first exoplanet in 1995, the European astrophysicists have announced to have found a first-type rocky planet around a star other than our Sun,”

but it failed to catch the negation in the second:

“The COROT exoplanet 7b was observed earlier this year, but its composition had been established at this time.”

(Also humorous is its translation of “581e” as “581st” — subtle!)

I guess I am encouraged that there’s still a need for human translators!