WonderQuest:  On the web since 1997...      

Curious sunrises, Egg universes, The Universe begins-- "preposterously"

Q: There was a very curious sunrise this morning: a solid, vertical column of light ascending from the just rising sun. I don't recall seeing anything like it before. Is this a marvel or merely a common occurrence that I have until now missed? --Lanney A., Sandia Park, New Mexico

[Lanney Atchley] Sun pillar, Sandia Park, New Mexico

A: It's a beautiful photo and the colored light is called a sun pillar. "Shafts of light that extend vertically from the sun are called sun pillars," says Lynch and Livingston of Color and Light in Nature. They are most often seen above the sun when the sun is low (1 to 2 degrees of the horizon). The pillars--as wide and the same color as the sun--are similar to the reflection the setting sun makes on a body of water.

Ice crystals, drifting down like leaves, cause the phenomenon. The crystals must be aligned almost horizontally--tipped slightly down. (Related: figures showing how ice forms a sun pillar.)

"These crystals fall in a wobbly way," says Bob McDavitt, MetService Weather Ambassador in Newton, Australia. Sunlight grazes the crystal bottoms and bounces down to your eye (if you're around). The wobbly fall of the crystals smears the image out vertically. Light seems to come from a vertical shaft instead of the actual stack of reflections.

Nearby pillars that form over streetlights in fog can vanish and reform almost instantly as a gust of wind realigns the crystals. Immersed in the diamond dust, you see an eerie three-dimensional effect.

How common? "It's like a tree falling in the forest or an iceberg breaking off from a glacier. Happening all the time, but not many of us are watching," says McDavitt. It doesn't take much to produce a sun pillar: setting or rising sun, a sky clear of low clouds but with sufficient cirrus clouds for a bank of ice crystals to reflect sunlight.

However, that depends on geography says Keith C. Heidorn, The Weather Doctor. "In New Mexico, they may be more rare due to lack of moisture in the atmosphere and the small number of days with snow on the ground."

Further Surfing:

USATODAY.com: Sky phenomena

The Weather Doctor: Sun pillars

AKM: Upper sun pillar

Jake's site: Ice crystals

Sundog: Sun Pillar

Q: I assume that the universe shape is more or less like an egg. At the surface of the "egg" is where all the galaxies lie. Inside the "egg" is nothing-- not a single star or galaxy. The Big Bang made all matter push away from the center of the "egg." Is my assumption correct? --Bambing, Quebec, Canada

A: It's not a bad assumption but you've got one thing wrong. We've discovered that the Universe is infinite (and flat: more about that next week). So, it has no shape in the sense of having an outside surface. It has no center, just a beginning. Space is expanding, as you say. Some kind of "dark energy" is pushing galaxies apart at ever increasing speeds.

Think of a big, black elastic contour bed sheet with yellow polka dots spaced about an inch apart. Imagine stretching the sheet uniformly to fit over an even bigger bed. That's how space expands. No part of the bed sheet becomes empty of polka dots. The dots, like galaxies, simply get farther apart. This effect is significant only for galaxies separated by large fractions of the observable Universe.

Q: Can you give a succinct explanation of the Big Bang Theory? --Tony D.

[NASA] Hubble's panoramic portrait of a vast star-forming region-- the 30 Doradus Nebula

A: It's been 70 years since we've come up with the incredible Big Bang theory of creation and it looks like we had it right--no matter how crazy it seems.

"We're stuck with this preposterous universe," says University of Chicago astrophysicist John Carlstrom after a recent discovery supporting the theory.

Here's our current thinking about the Big Bang:

A long, long time ago (14 billion years) the entire Universe was a mere speck--the size of a head of a pin (one millimeter across). This was not quite the beginning of time but rather the tiniest of shading (10^-43 seconds) later. Then, matter consisted of its most elemental parts--quarks and leptons --which are point-like in size. All matter could fit within a grain of sand because, essentially, it had no size.

At the instant of creation (or at least 10^-43 seconds later, which is when our theory starts), the Universe started expanding... with a bang. Elementary particles hurled away from each other in a blazing fog of energy. As the Universe expanded, it cooled, eventually enough so the elemental particles evolved into a tightly-packed jumble of photons, electrons and protons--still too dense for light to penetrate. The Universe expanded and cooled more until, 300,000 years later, hydrogen atoms formed.

When the particles moved together to form atoms, they opened small space hunks. Then, bits of light (photons) found paths to shine in all directions. Today, we can still see that "fossil radiation" (as Carlstrom puts it) that is commonly known as Cosmic Microwave Background (CMB) and provides data essential to test the Big Bang theory.

Gravity kicked in and pulled hydrogen atoms together to form stars, galaxies, and other cosmic structures. That's how it all began, we think. However, there are loose ends flying around. For one thing: what's going to happen? How will the Universe evolve? Will it just keep expanding forever or will it stop and converge back to a speck for another Big Crunch/Big Bang? If it keeps expanding, will matter thin out to nothing? University of Chicago scientists and others found answers to these questions recently (September 2002) and next week's WonderQuest will discuss the answer.

Further Surfing:

WonderQuest Expanding space

WonderQuest The Big Bang

WonderQuest Outside the space pinhead

space.com: Dark energy finding

(Answered Jan. 24, 2003)