According to Colwell

Florida’s State Board of Education voted (4-3!) this week to include evolution (for the first time!) in the science curriculum of public schools. (Previously the concepts of evolution were taught in Florida, but the curriculum referred only to things such as “change over time”. My own recollecton of Honors Biology in a Florida High School are that our class had a debate on the topic of evolution. I was one of three or four on the side arguing in support of evolution, and the opposing group argued for Biblical creation. I do not recall any instruction on the matter in class at all.) The new standards were apparently headed for defeat until a so-called compromise was reached by inserting the words “the scientific theory of” before the word “evolution”. This concisely illustrates the anti-evolution advocates’ lack of understanding not only of evolution but also of what “scientific theory” means.

Last night we had a beautiful view of the total lunar eclipse from Orlando. In some ways it was more impressive to see it during the partial phase when only part of the Moon was in the shadow of the Earth. The curved shadow of the Earth across the face of the full Moon provided ample evidence that the Earth was a sphere long before it was finally circumnavigated. Maybe Sherri Shepherd of “The View” got a look.

Lunar eclipses occur when the Moon is on the opposite side of the Earth than the Sun so that the Earth’s shadow falls on the Moon. If the orbit of the Moon were in the same plane as the orbit of the Earth around the Sun, we would have a total lunar eclipse every full Moon. The Moon’s orbit is inclined to the plane of the Earth’s orbit (the ecliptic) by a little over 5 degrees. So the Moon crosses the ecliptic twice each month, but for a lunar eclipse to occur, that crossing point must occur when the Moon is full (meaning that it is on the opposite side of the Earth than the Sun). In rough numbers that occurs twice a year. However, the size of the Earth’s shadow at the distance of the Moon is only a couple of times the size of the Moon, so depending on the exact timing of the Moon crossing the ecliptic, the Moon may not pass through the shadow entirely (resulting in a partial eclipse), or it may only pass through the penumbral shadow (where only part of the disk of the Sun is obstructed by the Earth). Nevertheless, I could not help but wonder how the local Orlando television station got the idea that it would be 40 years before the next total lunar eclipse. In fact the next total lunar eclipse will be in December 2010. The gap between this one and that 2010 total eclipse is actually unusually long. There will be 85 total lunar eclipses in the 21st century, or nearly one every year.

Because the Moon’s orbit is not only inclined to the ecliptic, but is also not circular, there are additional differences in the frequency of eclipses as the orientation of the Moon’s elliptical orbit changes with time and the distance of the Moon from the Earth (and hence the size of the shadow) also changes. Combining the time for the Moon to go around the Earth, the time between two full Moons, and the time for the Moon’s elliptical orbit to return to its same orientation with respect to the Earth and the Sun, we get a cycle for when eclipses will repeat with nearly the same duration and visibility (this holds for solar eclipses as well, which are much more finnicky than lunar eclipses because the shadow cast by the Moon is much smaller than the shadow cast by the Earth). This cycle is called the Saros cycle and is a little over 18 years. So I still don’t know where the local weatherman got his 40 year figure, but the station’s web site has the correct information now.

The more spectacular solar eclipses are far more rare due to the small size of the Moon’s shadow. There is a nice total solar eclipse visible across the United States on August 21, 2017, and another one on April 8, 2024. In the meantime, you’ll have to go quite far to catch one.

Nearly 20% of the delegates at the Democratic National Convention will not be delegates chosen by the democratic process, rather they will be part of the classic Old Boys Network: officials and party power brokers who want to make sure the masses don’t mess things up. It’s the same ancient outdated politics that gave us the electoral college instead of a direct election for president. Now, with a close race in elected delegates between two candidates, it is quite likely that neither Hillary Clinton nor Barack Obama will have enough delegates for the nomination without the so-called “superdelegates”. That means the nominee will not be chosen by people who voted for one candidate or the other, but by nearly 800 party insiders. The DNC should do away with these superdelegates altogether, or they face a repeat of the 1968 debacle that put Richard Nixon in the White House.

I find it hard to believe, but the end of Cassini’s original 4-year mission is just around the corner, this June 30. Planning has been underway for a couple of years on a two-year extended mission. That mission will take Cassini through Saturn’s northern spring equinox (the moment when the Sun passes through Saturn’s equatorial plane from its southern hemisphere to its northern hemisphere). While not official, that makes the name Cassini Equinox Mission a logical choice for the extended mission, and while less economical, certainly more comprehensible than “XM”.

The discussion at last week’s Cassini Project Science Group meeting centered around plans for an “XXM” which, hopefully, will soon be known as the Cassini Solstice Mission. That name would be appropriate if plans succeed to keep Cassini running through the summer of 2017 when the north pole of Saturn (and therefore also its moons) is pointed most directly at the Sun (that is, Saturn’s northern summer solstice).

So, what’s the big deal about Saturn’s solstice? Now that Cassini has spent four years studying the Saturn environment (about 1/8th of a Saturn year) we have seen changes in just about every component of the Saturn System that take place over the seasonal timescale. The atmosphere of Saturn undergoes exceptionally strong seasonal variations because the rings cast an enormous shadow on one hemisphere near solstice, and virtually no shadow at all near equinox. Titan’s lakes currently appear to be largely confined to the wintery north pole. What will happen to those lakes as summer comes to the north? Enceladus’s southern pole geysers are not driven by the Sun, but there are indications that it and the dusty E ring it feeds undergo large changes on timescales of several years. Solar radiation pressure pushes the dust particles in the E ring; this may lead to large-scale deformation and warping of the ring as the Sun gets high above the ring plane toward solstice. The main rings are also exhibiting a variety of phenomena that unfold over days, months, and years. The F ring in particular seems to be host to a chaotic environment where moons form and break apart. Waves in the rings propagate across the rings at just a few millimeters per second. With many years of observations we will be able to see real structural changes in the rings as the moons producing these waves undergo small changes in their orbits due to interactions with other moons. There are also a myriad unanswered questions that simply require more observations to answer, such as what is responsible for keeping all those gaps in the rings open, and what do the north polar regions of the icy satellites look like?

There’s no fixed timetable, but the end of the Cassini Equinox Mission is not until June 2010, so it could easily be another year before there is firm guidance from NASA headquarters on the Cassini Solstice Mission. One factor that will be considered is what to do with the spacecraft at the end of the mission. In order to avoid possible biological contamination of Titan and Enceladus, Cassini may be crashed into Saturn after some exciting flights through the gap between the rings and the planet. Or it may be crashed into an icy moon, or perhaps even sent off to interplanetary space, though this final option would negatively impact the science returned from the Saturn system in the solstice mission.

This is a very cool and very fun visualization tool that lets you ride along with the Cassini spacecraft as it tours the Saturn system. The path of the spacecraft as well as the pointing of the spacecraft, are taken from the actual data files describing Cassini’s activities. Check it out.

Normally I have no patience for movies whose plot depends on a miscommunication. You know the kind: the hero leaves a note for the heroine explaining what he’s doing, but she doesn’t get the note and assumes he’s left her, and then she goes off and marries a jerk. I’m not interested in any plot that could be resolved by two people having a brief conversation along the lines of “Did you get my message?” Best Picture nominee Atonement is superficially a tragic love story, doomed in part on a misplaced note. But it is a series of events that lands Robbie (James McAvoy) in jail rather than in the arms of Cecilia (Keira Knightley - random aside: my daughter and I found ourselves visiting the Cabinet War Rooms in London with Knightley in the summer of 2005 where I’m guessing she was doing a little background research for this movie). And the movie is less about their love story than it is about Cecilia’s little sister Briony who screwed things up for them in the first place. But the movie suffers from conflicting interests in storytelling: Briony’s efforts to atone for her childhood misdeed and Robbie and Cecilia’s efforts to reunite and put the embarrassment of the past behind them. Ultimately, I felt it gave neither story sufficient due. The love story is poorly established and therefore not as compelling as it should be, and Briony’s story is left aside for a long stretch in the middle of the film as we see Robbie slogging through northern France at the start of World War II. This sequence does feature one staggeringly heroic shot of the chaos at the beach at Dunkerque. That minutes-long shot by itself might have motivated some of the votes for this movie’s Best Picture nomination.

Laura Linney is nominated for an Academy Award for Best Actress in this personal movie about a woman and her brother (Philip Seymour Hoffman) dealing with their estranged father’s dementia and declining physical health. Wendy Savage (Linney) is an aspiring but unproduced playwright in New York City who earns a living as a temp. She has a physical relationship with a married neighbor, but seems to be more emotionally involved with his golden retriever (and who can blame her?). Her brother Jon lives in Buffalo where he is a professor of depressing theater (i.e. Bertolt Brecht). When their father suddenly finds himself homeless and demented, they find themselves suddenly responsible for taking care of a man who never took care of them. Absent when they were in diapers, Wendy is confronted with her father in a diaper. Jon argues the pragmatic approach of a nursing home; Wendy is wracked by guilt. While her father’s life slips away, Wendy is stuck in neutral, never having really started her life. She works as a temp. She conceals her writing failures from her brother. She is engaged in a relationship that she knows has no long-term prospects. The movie is about her coming of age in middle age.

The United States entered the space race 50 years ago today (okay, I wrote this on the anniversary, but am posting a day late) with the successful launch of the Explorer 1 spacecraft. Although Explorer 1 was a modest 30 pounds and quite simple by the standards of today’s spacecraft, it made an important scientific discovery. The spacecraft was built at JPL, where I happen to be at this moment for a Cassini Project Science Group meeting, and where there is a distinctly festive air and displays of the history of JPL’s involvement in the U.S. space program. The key instrument on Explorer 1 was a Cosmic Ray Package that was essentially a Geiger counter for detection of charged particles. The flux of charged particles was much less than expected at high altitudes (>2000 km), but equal to the expected value at lower altitudes. James Van Allen, lead instrument scientist on Explorer 1, hypothesized that the instrument was saturated by radiation from charged particles trapped in the Earth’s magnetosphere at high altitudes. The confirmation of this by Explorer 3 a few months later earned these regions the name they are still known by: the Van Allen radiation belts. Because of the high energy of the particles in these toroidal regions around the Earth, they pose a hazard for astronauts as well as spacecraft electronics. The space shuttle and space station orbit safely beneath the belts. Pics of the festivities at JPL coming shortly.

Hmm. I think the pictures are on my phone, but they didn’t translate to my computer last time I synched.