Top Shelf Astronomy 201 Courses

Looking for an astronomy class a little beyond the basics, but not requiring a PhD and taught by the experts? Here are four recommendations that are “out of this world.”

 

University Astronomy 101 in Your Pocket

Now that you have discovered how much you love astronomy, do you regret not paying attention in your college classes, or kick yourself for not even taking an Astronomy class when you had the chance?

It’s not too late. In fact, you can listen and view Astronomy 101 classes from some of the top universities or listen to invited lectures by the scientists who are making the great discoveries we read about each day. Best of all, it’s completely free, and you can take it with you on your iPod or iPhone. A new world of learning is available to you at iTunesU.

All you need is a computer and internet access. Download Apple’s completely free iTunes program for the Mac or the PC. Go to the iTunes store and click on iTunesU listed on the left hand menu.

Gravitational Lensing in a Wine Glass

On May 20, 2009, Prof Patricia Burchat, the Chair of the Department of Physics at Stanford University, presented the last lecture in the 10th season of the Silicon Valley Astronomy Lectures. She gave what I have found to be the best demonstration of gravitational lensing.

Of course, there are many examples of gravitational lensing in Hubble photos of galaxies. These are sometimes called Einstein rings and are the direct result of the bending of light by gravitational fields.

Modern Cosmology was Founded on Luck

The Hubble Constant, which describes the velocity-distance relationship for galaxies, is the foundation of modern cosmology. It establishes the time and distance scale of the universe and the dynamic nature of the galaxies since the beginning of time. It is all the more remarkable that the original data Edwin Hubble took was flawed.

Last Man on the Moon Speaks at Linda Hall Library

Harrison Schmitt, the last man to walk on the moon, spoke to a full house at the Linda Hall Library on Sept 2, 2009, as part of the “To the Moon and to the Planets Beyond” lecture series.

Schmitt left the moon on December 14, 1972 as part of the Apollo 17 mission. He was the only geologist to visit the moon, receiving a PhD in Geology from Harvard. And as the only non military and non professional test pilot among the Apollo crews, much to the consternation of the NASA controllers on earth, he was prone to falling while hunting rocks on his moon walks. In this photo, his suit is covered in moon dust from his close up encounters.

The Difference Between Astronomy, Astrophysics and Cosmology

Astronomy is the study of what you see in the sky and the dynamics of objects in space. I think of it as about what you can see when you observe the sky with your eyes or through a telescope. What I love about astronomy is that it is accessible to everyone. You walk outside on a clear night and you can participate in astronomy

This is the age of the great space observatories and all their incredible pictures are available to all on the web, like the Hubble Gallery.

Colliding Galaxies at Your Fingertips

When we look at a few Hubble photos of distant galaxies we may get the impression the universe is a static place. Other than the occasional supernova brightening, the galaxies we see haven’t changed much over the hundred years of observational history. But, it may well be the dynamics of energetic galactic collisions that created the variety of visually distinct galaxies we see today.

Though not so common today, images of many colliding galaxies, frozen in time, have been captured. In 2008, NASA and the Hubble Space Telescope Science Institute released a collection of 59 colliding galaxy images, shown above.

Book Review: The Alchemy of the Heavens by Ken Croswell

Astrophysicists sometimes use familiar words, but in a very different way than we are used to. Take for example the term metal. To an astrophysicist, a metal is any element with an atomic mass greater than Helium’s.

That’s because only hydrogen and helium were created during the big bang and all higher atomic mass nuclei had to have been created in some stellar process. This story of nucleosynthesis and what it tells us about the structure of the universe, the origins of our galaxy and stellar evolution is detailed in Ken Croswell’s book, The Alchemy of the Heavens, published by Doubleday, 1995.

“Death Star Gamma-Ray Gun Pointed Straight at Earth”

“Death Star Gamma-Ray Gun Pointed Straight at Earth”

So read the headline on Fox News, March 5, 2008. This was no joke. In fact, it was based on nine years of observations on WR104, a Wolf Rayet star about 8,000 light years away in the constellation Sagittarius. It was first discovered in 1999 by University of Sydney astronomer Peter Tuthill.

Wolf Rayet stars, named after two 19th Century French astronomers, Charles Wolf and Georges Rayet, are the most massive stars, typically with greater than 20 solar masses.  Like Achilles of Greek Mythology, they have a short but glorious life. They live fast and die hard. They are the hottest, the brightest, the biggest and the most short-lived of all stars. And when they die, it is by a huge supernova usually resulting in a black hole.

The Stars of Sgr A* (Sagittarius A Star)

Figure 1. Measured (dots) and calculated (line) orbital position of S0-2 based on 16 years of observations. The orbit matches Kepler’s law perfectly. From Ghez, et.al., Astrophysical Journal, Aug 21, 2008.

Peer toward the Milky Way’s center in visible light, and you see clouds of dust and gas obscuring all the stars. But, switch to infra red, near 2.2 microns wavelength, and 1 million stars within 1 square arc second of the sky, come clear.

This region has the highest observed stellar density of the known universe. Using  a distance to the galactic center of 7.6 kpc (kilo parsecs), this translates to about 1 million solar masses per cubic parsec within 1 parsec of the black hole, hidden in the middle of this forest. Our nearby space has only about 1 solar mass per cubic parsec.

Two independent teams have been peering into the center of our galaxy, within a tiny square, 1 arc second on a side, and reported their latest results this year.

White Dwarfs Don’t Remain Silent

“They are like a hot lump of coal slowly cooling”, Ashley Yeager describes white dwarfs in her piece, “Dead – But Not Duds” in Science News, Oct 11, 2008.

White dwarfs, the dead corpse of a star with a mass less than about 1.4 solar masses, create in their final days, spectacular planetary nebula, such as the Helix Nebula, the Ring Nebula and the Cat’s Eye Nebula.

They have become especially famous since the early 1990s as standard candles in the measurement of the acceleration of the universe and the primary evidence of dark energy.

The Top Ten Astrophysics Discoveries of the Last 35 Years

David Letterman made famous his “Top Ten” List. Richard Talcott, a senior editor of Astronomy Magazine created a Top Ten List that Letterman would probably never put on his show. To highlight the 35th anniversary of the magazine, he came up with the “Top Ten Discoveries of the Last 35 Years,” published in Astronomy Magazine, Aug, 2008.

If you ask 10 astronomers for their list, you might get 11 different lists. If you look back over the last 35 years, what would you put on your list as the top discoveries? Before you read on, jot down your list.

Here’re the top ten entries of Talcott’s list:

The Giotti Space Craft: Mission to Comet Halley

In 1301, the medieval Italian painter Giotto di Bondone (1267-1337), observed Halley’s comet, which he memorialized as the star of Bethlehem in his painting, Adoration of the Magi.

Almost 700 years later, he was honored by having his name carried by the first space craft mission to visit Comet Halley, Giotti. This was also the first mission of the European Space Agency.

The 212th AAS Mtg in St. Louis, MO, June 1-5

Three themes permeated many of the sessions at the recent American Astronomical Society meeting in St. Louis, MO June 1-5, 2008.

1. The International Year of Astronomy (IYA) 2009 is going to be a BIG, world wide event.
2. The number of excellent astronomy related web resources are growing faster than any single individual can track them, let alone take advantage of them.
3. Data flow from the new ground based and space based observatories is escalating and we are going to be inundated with new discovery announcements from now on.

Expectations for the Large Hadron Collider

In “The Origins of the Universe: A Crash Course”, by Brian Greene, posted in the OpEd section of the New York Times, Sept 12, 2008 , Greene, a professor of Math and Physics at Colombia University, offers four possible revolutionary advances the Large Hadron Collider (LHC) may uncover.

The LHC is a 17 mile long track with 10,000 superconducting magnets, costing the international community over $8 billion. Last week it turned on. Protons circulate 11,000 times around the track each second creating half a billion head-on collisions. The energy of each collision will quickly “convert to a broad spectrum of other particles,” such as: Higgs Bosons, supersymmeric particles, transdimensional particles, and micro black holes.

The Gamma-Ray Large Area Space Telescope (GLAST) – Latest Eye in the Sky

We have all suffered through the limitations of viewing the stars from beneath the blanket of our thick atmosphere, especially thickened by summer humidity here in Kansas.

While ground based optical observations suffer from dust and small atmospheric fluctuations, some wavelengths are just not possible to view due to absorption by water vapor and other gases. Space based telescopes, orbiting above the limitations of the atmosphere, have literally opened our eyes to higher resolution and extended our viewing to higher and lower wavelengths.

With its successful launch on June 11, 2008, GLAST, the Gamma-Ray Large Area Space Telescope, became our latest eye in the sky. It extends our frequency range into the highest energy yet, from 10 keV to 300 GeV.