Vol. 27 No. 3 December 1997

THE DECEMBER MEETING

The December meeting of the Ogden astronomical Society will convene in the Ott Planetarium on the Weber State University campus at 7:30 P.M. next Thursday December 11, 1997.

A special guest speaker, Mr. Steve Sargent, will discuss the recently launched Cassini project to Saturn. Mr. Sargent is an engineer employed at Hercules, the company who built the solid boosters for the Titan launch vehicle.

Also at this meeting Bruce Fischer and Elgie will display some recent CCD images they have taken of some near earth asteroids. They will describe how they locate the objects and how they are beginning to track and search for these potentially dangerous little worlds.

  THE PLANETS ARE SHOWING OFF IN THE SOUTH WEST

If you haven't already had the opportunity to check out the grand alignment of the major planets in the evening sky you only have a few days left. By the time you read this the moon will have already made its way through the planet field and Mars may be too low in the evening sky glow to see clearly.

The best two days for viewing the moon in conjunction with the planets was on December 3 and 4 when the thin crescent was moving eastward by Venus, past Jupiter and was approaching Saturn. However, the planets still remain a beautiful sight, just after sunset, say around 6:30 or 7:00 P.M. Starting on the south western horizon, look for orange Mars near the horizon, then bright Venus to the upper left, then Jupiter nearly south-south west and continuing east ringed Saturn is just east of due south, about 45 degrees above the horizon.

If any members have attempted photography of this alignment, bring your work along to the December 11 meeting and show off a bit. There is always time to discuss issues, items, current events, sketches and photos during the rap session that follows every meeting.

 
  OTT PLANETARIUM AND THE HOLIDAY SEASON SCHEDULE

Wednesday December 10 and 17 WSU's Ott Planetarium will present two holiday shows, The Winter Sky at 6:30 p.m. and Seasons of Light at 7:30 p.m. Star parties, telescope observing, hosted by the Ogden Astronomical Society, will be held at 8:30 p.m. each night if weather permits. The Ott Planetarium is in the Lind Lecture Hall. $1 per show for students and children, $2 per show for public. OAS members are admitted free when they assist with the telescopes. (Observing session is free.) Call 626-6855 for details.

 WHAT'S WORTH VIEWING THIS MONTH?   Not everything is astronomy related but it is still good stuff:  

Wednesday December 10, Discovery Channel, TITANIC: UNTOLD STORIES. Interviews with survivors and stories never told before are presented in this documentary of the great ship and the night she perished. Times are uncertain, check local listings. Repeated Sunday December 21.

Tuesday December 16, NOVA: "Curse of T. Rex" Controversy rages over who owns the finest Tyrannosaurs Rex fossil. KUED Ch. 7 at 7:00 P.M. Repeated December 21 at 6:00 P.M.

Tuesday December 16, "TITANIC". Original footage and interviews with the few remaining survivors, chronicles the brief life of the great ship and the rediscovery of the wreck 7 decades after the accident. KUED Ch. 7, 8:00 P.M.

Friday December 26, DISCOVERY NEWS: TOP TEN SCIENCE STORIES OF 1997. A look back to this year's greatest science stories. Check local listings for specific times. Repeated Dec. 27 and 28.

The following is taken from the Internet web site The Astronomy Cafe which can be found at: www2.ari.net/home/odenwald/cafe.html

Ask The Astronomer...
 

Q. Are black holes now considered to be 'proven' real objects in the universe?
 

A. I think the circumstantial evidence for the existence of black holes is now so strong that it would be hard not to consider them to be real objects in the universe. The strongest evidence we have is for the stellar-mass and supermassive black holes. General relativity, however, predicts that if the conditions are right, black holes can have any mass. Once you open the floodgates by accepting the existence of one kind of black hole, you have opened the question of whether other less massive ones may also exist, and under what conditions such holes could be spawned. The favored spawning ground for sub-stellar black holes is during the first few minutes after the Big Bang when matter was rattling around with enormous collisional energies.

I have watched, during the last three decades, the evidence mount with astonishing speed, culminated by the fantastic observations by the Hubble Space Telescope. It is hard to imagine that some other mechanism can be the host for the phenomena we see in the cores of quasars and active galaxies. And it is not that theoreticians have not been actively pursuing other non-black hole possibilities. But one by one, I have seen these other ideas succumb to new observations, while the simplest explanation predicted, and even demanded by general relativity grows in strength.

There have been many episodes in scientific advancement when a new idea was initially met with some discomfort, but after a few decades and the accumulating weight of evidence, the community began to grow comfortable with the new idea. Not too long ago, many physicists did not 'believe' in the existence of atoms, or in quarks. They are now hallowed members of the modern repertoire of things in nature.

Years ago, a young girl wrote to a newspaper asking whether Santa Claus existed, the answer was " Yes, Virginia, there is a Santa Claus". So far as I am concerned, "Yes, dear reader, there are in fact black holes!"
 

Q. What ever happened to the rival theories to Big Bang cosmology?
 

In the last 70 years, there have been many seriously-considered alternate theories to describing the large-scale properties of the universe. Here is a partial list of them, and what happened to them:
 

DeSitter Cosmology ca 1917

The universe is presumed to be entirely empty of matter, but expands exponentially in time because of the presence of a non-zero cosmological constant. This refutes nearly every observational fact now available, including the actual rate of expansion which follows a linear, Hubble law, not an exponential expansion law with time. Also, the density of matter in the universe is not zero because we are here, and so are a lot of other stars and galaxies!
 

Einstein Static Cosmology ca 1917

The universe does not expand, and is static in time. The cosmological constant is precisely tuned to balance the attractive tendency of matter. Like DeSitter cosmology, it also fails to agree with modern observations, because the universe is expanding linearly with time. It is also unstable to the slightest perturbation in the value of this constant.
 

Lemaitre Cosmology ca 1924

The universe started with a 'big bang' with no cosmological constant. The initial state was a giant radioactive atom containing all the matter in the universe near absolute zero. This theory agrees with the observed expansion, but fails to explain the existence of the cosmic background radiation and the universal abundances of hydrogen, helium and deuterium.
 

Steady State Cosmology ca 1950

Developed by Fred Hoyle and Thomas Gold, it proposes that the universe has been expanding for eternity and that new galaxies are created, atom by atom, in intergalactic space 'out of empty space'. This theory had its heyday in the 1950's and 1960's, but was never able to explain convincingly where the cosmic background radiation came from, why it is so isotropic, and why its temperature is fixed at 2.7 K. It also provided no clues as to why there ought to be a universal abundance ratio for hydrogen, helium and deuterium.
 

Cold Big Bang Cosmology ca 1965

Developed by David Layzer at Harvard, it proposes that the Big Bang occurred, but that the initial state was at absolute zero and consisted of a pure solid of hydrogen. This fragmented into galaxy-sized clouds as the universe expanded. It provided no explanation for where the cosmic background field came from and why it is isotropic and at a temperature of 2.7 K.
 

Hagedorn Cosmology ca 1968

Physicist Robert Hagedorn proposed that all of the details of big bang theory are probably true, except that the early history of the universe had a limiting temperature of about 1 trillion degrees because the structure of matter has an infinite ladder of 'fundamental particles' out of which electrons, protons and neutrons are constructed. This has been refuted with the discovery that quarks exist which place any limiting temperature for the early history of the universe at temperatures well above 1000 trillion degrees.
 

Brans-Dicke Cosmology ca 1955

Einstein's equation for gravity in general relativity is modified to include a 'scalar' field. This field causes the value of the constant of gravity to change slowly over billions of years. This also leads to a modification of the early history of the universe. Experimental searches for a change in the constant of gravity show that it has not changed to within experimental error during the last 2 - 3 billion years. It would cause the evolution of the Earth-Moon system to be significantly altered, and the evolution of the Sun to be severely modified. Neither of these effects have been observed.
 

Old Inflationary, Big Bang Cosmology ca 1980

Developed as a 'toy' model by Alan Guth in 1980. The Inflationary era which ended 10^-34 seconds after the Big Bang caused the nucleation of innumerable 'bubbles' of true vacuum which merged together to form a patina of matter and radiation in a very lumpy configuration. The cosmic background radiation, however, shows that the universe is very smooth to 1 part in at least 10,000 since about 300,000 years after the Big Bang. There is no evidence for such a turbulent and lumpy transition era.
 

Oscillatory Big Bang Cosmology ca 1930

This a possible modification to Big Bang cosmology that differs only in that the current expansion will be replaced by a collapse phase and then an expansion phase etc. There is no evidence that there was ever a prior expansion-collapse phase. The universe also does not seem to have enough matter to make it a 'closed' universe destined to recollapse in the future; an important requirement for any future oscillation cycle.
 

Big Bang Cosmology with added Neutrino Families ca 1970

Big Bang cosmology is largely correct, except that to solve the 'missing' or 'dark' matter problem, new families of neutrinos have to be added to the universe. This would change the cosmological abundance ratios of helium and deuterium relative to hydrogen so that the current observed values no longer are possible. There is also no experimental evidence that more than 3 types of neutrinos exist; and these are already consistent with the measured cosmological abundances.
 

Chronometric Cosmology ca 1970

Developed by I. Segal at MIT, it proposes that space-time has a different mathematical structure than the one that forms the basis for Big Bang cosmology. So far as we can tell, the major disagreement is in the rate of the expansion of the universe which comes out as a quadratic law between distance and expansion speed, rather than the linear Hubble Law. This proposal seems to be inconsistent with what has been observed for distant galaxies during the last 3-4 decades. There may be other disagreements with Big Bang cosmology, but Chronometric cosmology has not been explored deep enough to make testable predictions in these other areas.
 

Alfven Cosmology ca 1960

Developed by physicist Hans Alfven, it proposes that the universe contains equal parts of matter and anti-matter. No explanation is made for many of the other observational facts in cosmology. If there were equal parts of matter and anti-matter, there ought to be regions in the universe where these were in contact to produce X-rays or gamma rays due to the annihilation process. No such large-scale background has ever been detected that can be attributed to proton or electron annihilation.
 

Plasma Cosmology ca 1970

The matter in the universe, on the largest scales, is not neutral, but has a very weak net charge which is virtually undetectable. This causes electromagnetic forces to dominate over gravitational forces in the universe so that all of the phenomena we observe are not the products of gravitation alone. This is an intriguing theory, but other then denying their importance, it cannot easily explain the origin of the cosmic background radiation, its isotropy and temperature, and the abundances of helium and deuterium.
 

So, who says that astronomer's are suppressing alternate ideas to Big Bang cosmology? The problem is that none of these other ideas satisfy all of the observational evidence as well as Big Bang cosmology does!

Elgie's Pictures of The Month

First image of M42 120 seconds Second image 240 seconds
 

M42 (NGC 1976), Position 05329s0525, the "Great Nebula in Orion" considered the finest example of a diffuse nebula in the sky. For the amateur, there is no other object in the heavens so perfectly suited for observation by a low power wide-angle telescope.

These images where taken on 11-13-97 at 05:01:20 a.m. and where taken using my ST-6 CCD at f/10, guided using my new ST-4 CCD camera. With this new CCD I am able to take images of up to one hour with the ST-6 CCD and as long as I want with a 35mm camera. Elgie