Philosophical Society of Washington

Minutes of the 2,212th Meeting

President William Saalbach called the 2,212th meeting to order at 8:17 pm November 17, 2006 in the Powell Auditorium of the Cosmos Club. The recording secretary read the minutes of the 2,211th meeting and they were approved.

Mr. Saalbach introduced the speaker of the evening, Mr. H. John Wood of the NASA Goddard Space Flight Center. Mr. Wood, the lead optics engineer of the Hubble Space Telescope Program, spoke on Fifteen Years of Astounding Images by the Hubble Space Telescope.


Born in Baltimore, Mr. Wood, at age eight, looked at the Moon through the telescope of the Northwood Observatory. Now Baltimore has become a rich center for astronomy.

When the first Hubble pictures came back, John Mangus, then the man in charge, was disappointed with the resolution. Mr. Mangus, Mr. Woods’ boss, was assigned to figure out what the problem was. Mr. Wood, as a good performance reward, was given the broken Hubble.

The first guess about the problem was that a mirror was not polished smoothly. It turned out the mirror was very smooth, but it was with the wrong prescription. On the first service trip up to Hubble, they installed corrective lenses. The shape had to be 2.2 microns from the true, and this correction had to be put into a lens the size of a dime.

Mr. Wood watches the Shuttle go up from Bowie. It goes up fast at first to get out of the atmosphere. Five minutes after launch, he can look from Bowie to the southeast and see it low in the sky.

He showed pictures of servicing mission 3B, when they added some new solar panels and the Advanced Camera for Surveys and removed the Faint Object Camera. We learned that space walks are short because people’s hands get tired in the pressurized gloves, even though the 800 pound Advanced Camera for Surveys could be moved with one’s fingertips.

He showed pictures of Mars. All the geographical features were in great detail. The Mars Polar Cap is actually condensed CO 2. For some reason, the southern hemisphere of Mars is much more pockmarked by craters than the north.

There was a really nice, detailed picture of Jupiter. One precise, dark spot was the shadow of Jupiter’s moon, Io. Jupiter radiates 2.5 times the energy it absorbs from the Sun. They think it has a core of liquid metallic hydrogen.

Pictures of Gliese 220B, a brown dwarf, from Mount Palomar and Hubble showed the advantage of Hubble. The Mount Palomar image showed a big blob with a little blob on the side. The Hubble image showed the big blob, the little blob, and little bubbles of matter all around the star and a needle of material shooting out that was completely missing from the Mount Palomar image.

There was a picture of Betelgeuse, a star about six times size of earth’s orbit. Even Jupiter’s orbit is smaller than Betelgeuse by about a third.

He showed a picture of the Orion Nebula, where 3000 stars are currently emerging from the dust cloud. Stars also emerge from EGGs (Evaporating Gaseous Globules).

In the Eagle Nebula, NASA found pillars of dust light-years long. New stars peek out from the pillars. Stars in the globular clusters are born together and may have common characteristics that differentiate them from stars of other clusters. The energy from the new stars sculpts and lights the dust, producing fantastic, eerie shapes. One pillar of dust in the Eagle Nebula is 9.5 light-years high, about twice the distance from Earth’s Sun to the nearest star. The columns result when energy from the young stars blows away the rest of the dust and leaves the columns.

He showed pictures of supernova remnants and observed that there was a supernova in 1054, during the Battle of Hastings. Both sides said the supernova was a sign they were winning. You and I, he said, are made out of material from a supernova: calcium, iron, and a lot of other chemicals.

He said Andromeda is one of his favorite galaxies, but it is heading our way and will probably eat the Milky Way for lunch one day. Andromeda is the big Kahuna of our local group.

Vera Rubin, one of our previous speakers and members, discovered that the rotation of Andromeda is not like planets. It is rotating really fast, and even the stuff farther out from the center is rotating fast. This discovery was a precursor to the discovery of dark matter.

Andromeda is so large it will fill your binoculars. Hubble was able to get down to the nucleus of Andromeda. It’s a triple nucleus. The smaller ones are smaller galaxies that Andromeda has eaten on its way to getting really big.

He showed a picture of The Mice, two spiral galaxies that interact. When they get close, they eject arms toward each other.

He described gravitational lensing. This occurs when light from a distant object passes a large mass like a galaxy. The gravitation of the massive object bends the light rays and can produce a distorted or transformed image of the object reflecting or emitting the light. It is an interesting phenomenon, but the gravity is not a good lens.

He discussed the makeup of the Universe. It now appears it is about 2/3 dark energy and 1/3 dark matter. There is a smidgen, 4%, of free hydrogen and an even smaller part, 2%, consists of stars.

A study hot off the press, released the day before, indicated there is a supernova in the center of each of the extremely distant galaxies. These are galaxies from nine billion years ago, and the most distant supernovas ever observed.

He closed with a beautiful composite picture of earth from space. He also observed that new technology has enhanced our understanding of the Universe.

He invited questions.

Does the repulsive force change over time? Indications are that it does not, he said. While it is audacious to think that physics may be constant for 9 billion years, that appears to be the case.

In answer to questions, he discussed means of determining distance, the demotion of Pluto from planet rank, and some of the Hubble discoveries. Hubble researchers have discovered the greatest number of other planets. Other discoveries he credits to Hubble: That dark energy permeates the entire universe, the energy of the vacuum, the importance of supernovas, and extra solar planets.

Hubble is as close to earth as it is because it needs to be serviced. The next one, the James Webb, will be further out. About 300 American astronomers and between two and three thousand from elsewhere have used Hubble. Between six and ten thousand amateurs have also used it over the years.


Mr. Saalbach presented Mr. Wood a plaque commemorating the event. He announced the next meeting. He made a pitch for support of the Society. He made the parking announcement.

Mr. Saalbach introduced Robert Hershey, chairperson of the nominating committee. Mr. Hershey announced the committee’s slate of office candidates and invited nominations from the floor.

Finally, Mr. Saalbach invited everyone to stay for the social hour and adjourned the 2,212th meeting at 9:52 pm.

Attendance: 77
Temperature: 9° C
Weather: Cool

Respectfully submitted,

Ronald O. Hietala
Recording secretary

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