It’s hard to tell from the bio’s I’ve read.  “… a degree in Astronomy and Astrophysics from .... “ tends, by the singular subject, to indicate it’s a single degree with a plural title. 

Oh, I see the problem now.  I deleted a whole section from my original text prior to posting, and left the ultimate sentence errantly in tact.  It was a comment on something else I decided not to include because I couldn’t defend the position… Anyway, you’re right.  Leaving it in there left an awkward (and incorrect) conclusion…

I’d delete it now except that would orphan the whole rest of the discussion.  :)

… A degree is not a profession.

Agreed…

When referring ambiguously to the speed of light, a vacuum is implicit.  The vacuum is in fact the medium.  In the Cherenkov effect, the particles are exceeding the speed of light in the medium in which it travels.

So, it’s possible for something to travel faster than light within a medium where the speed of light is lower than 3x10^8m/s.

I wonder if there’s any possibility of the existence of a medium in which the speed of light is greater than 3x10^8m/s.  I mean, even in a wormhole (SAGAN and HAWKING’s references) the speed of light is inviolable.  It’s only faster than the “Normal Space” path.

TonyPhillips - 29 April 2009 03:39 PM

...errantly in tact. 

I have never seen this particular typo before - I like it!

Bob

You’re on a roll there, buddy.

Hmm,

in my 3rd year undergraduate studies, I elected to study Astronomy (which was housed in the dept of Physics) After 2 lectures, I gave up and decided to take the slightly easier course in Quantum and Nuclear Physics.

I mention this simply to point out that astronomy is full of Physics and higher mathematics. To say an astonomer is not a Physicist is like saying a guitarist is not a musician. (Though i woudl also admit many of you may have already concluded this . . . :) )

Cheers

Here is some background information from Encyclopaedia Britannica under the entry “extrasolar planet”:

__________________________________________________________________________________________

also called exoplanet any planetary body that orbits a star other than the Sun. The first extrasolar planets were discovered in 1992. Nearly 350 are known.

Because planets are much fainter than the stars they orbit, extrasolar planets are extremely difficult to detect directly. By far the most successful technique for finding and studying extrasolar planets has been the radial velocity method, which measures the motion of host stars in response to gravitational tugs by their planets. The first planet discovered with this technique was 51 Pegasi b in 1995. Radial velocity measurements determine the sizes and shapes of the orbits of extrasolar planets as well as the lower limits of the masses of these planets. A complementary technique is transit photometry, which measures drops in starlight caused by those planets whose orbits are oriented in space such that they periodically pass between their stars and the telescope; transit observations reveal the sizes of planets as well as their orbital periods. Radial velocity data can be combined with transit measurements to yield densities of transiting planets and
thereby limit the possible materials of which the planets could be composed. The first detected transiting planet was HD 209458 b in 1999. Both radial velocity and transit techniques are most sensitive to large planets orbiting close to their stars.

Between 5 and 10 percent of stars surveyed have planets at least 100 times as massive as Earth with orbital periods of a few Earth years or less. Almost 1 percent of stars have such giant planets in very close orbits, with orbital periods of less than one week. In contrast, Jupiter, which has the shortest orbital period of any large planet (i.e., any planet more massive than Earth) in the solar system, takes nearly 12 years to travel around the Sun. Even the closest planet to the Sun, tiny Mercury, requires 88 days to complete an orbit. Models of planetary formation suggest that giant extrasolar planets detected very near their stars were formed at greater distances and migrated inward as a result of gravitational interactions with remnants of the circumstellar disks from which they accumulated.

The most massive planets that transit their stars are made primarily of the two lightest elements, hydrogen and helium, as are the Sun and its two largest planets, Jupiter and Saturn. Some of these planets seem to be distended in size as a result of heating by their stars. The lowest mass transiting planets contain larger fractions of heavier elements, as do the smaller planets within the solar system.

The majority of extrasolar planets with orbital periods longer than two weeks have quite eccentric (elongated) orbits. Within the solar system, the planets, especially the larger ones, travel on nearly circular paths about the Sun.

Stars that contain a larger fraction of heavy elements (i.e., any element aside from hydrogen and helium) are more likely to possess detectable planets. More massive stars are more likely to host planets more massive than Saturn, but this correlation may not exist for smaller planets. Many extrasolar planets orbit stars that are members of binary star systems, and it is common for stars with one detectable planet to have others. The planets detected so far around stars other than the Sun have masses from nearly twice to thousands of times that of Earth. Most, if not all, appear to be too massive to support life, but this too is the result of detection biases and does not indicate that planets like Earth are uncommon.

Research in the field of extrasolar planets is advancing rapidly, as new technologies enable the detection of smaller and more distant planets as well as the characterization of previously detected planets. Almost all the extrasolar planetary systems known appear very different from the solar system, but planets like those within the solar system would be very difficult to find around other stars with current technology. Thus, as more than 90 percent of those stars surveyed do not have detectable planets, it is still not known whether the solar system is normal or unusual. The U.S. National Aeronautics and Space Administration’s Kepler mission was launched in 2009 and—using transit photometry from space, optimized to achieve unprecedented sensitivity for small planets with orbital periods of up to two years—aims to discover whether planets analogous to Earth are common or rare.

Jack J. Lissauer

[Wellie] To say an astonomer is not a Physicist is like saying a guitarist is not a musician.

In my experience, a musically illiterate amateur rock guitarist is much more likely gratuitously to introduce himself (and vociferously identify himself) as a “musician” than is a highly trained professional instrumentalist. I assume this is somehow compensatory.

Anyway: 1) Your analogy strikes me as rather illogical (a more logical, though equally irrelevant, analogy would be to say an astonomer is not a scientist is like saying a guitarist is not a musician). 2) An astronomer is not a physicist--although an astronomer and a physicist are both scientists. (A scientist, by the way, is someone who has completed his post-doc--Sagan’s was in California, can’t remember the institution now, alas--and who works as a scientist).

[TonyPhillips] Oh, and to keep this on topic, that quoted article made no mention of the method they used to discover this object.  Was it an occulting phenomenon or a wobble?  It HINTED that it was “Wobble,” but the direct reference was to something detected that was MUCH larger.

It seems the planet was detected with radial velocity, a method explained in the Encyclopaedia Britannica article above. A spectrograph was attached to a telescope in La Silla, Chile.