Star Birth

If you’ve been a reader of this site for long, you probably wondered when I’d get to starbirth in this list of seven cosmic wonders. Wait no longer—here it is! Starbirth is one of the great recycling mechanisms of the cosmos. It takes material that is floating around in interstellar space and, under the right conditions, coalesces that material into a star. The process is incredibly long compared to human life spans. Our own star began forming some 4.6 billion years ago. It will live for another 5 billion years and eventually evolve to a white dwarf star. Before it does, the Sun will swell up to become a giant star, shed most of its mass, and then slowly cool and shrink. All that material that it sheds will populate the interstellar medium, perhaps becoming part of new stars in the distant future. Supernova explosions also return elements to space, and those too will become part of new stars and planets.

Regions of starbirth are nearly everywhere we look in our own galaxy and in countless other galaxies, too. Astronomers study them in just about every wavelength of light possible, although infrared-enabled observatories and instruments have the best chance of peeking into the stellar creches to watch the process of stars being born.

The closest starbirth region that most of us have heard about is the Orion Nebula, some 1,500 light-years away in the constellation Orion. If you look closely at the blow-up of this image (far left), you’ll see swirls of clouds, and what look like jets emanating from some of the new stars. Newborn stars are chaotic, and they sculpt their birth nests as they form. They also light up their surroundings, creating reflection nebulae—clouds of gas and dust that glow in the reflected light. However, those clouds also give off infrared light because they’re being heated by the nearby stars. So, I give you a glimpse into the mysterious realms of starbirth, a process that is itself one of the seven wonders of the universe.

The Big Bang

I was watching a documentary program the other day and it kept talking about this “huge explosion that created the universe” and referring to the Big Bang. The writer really should have known better, since I know the person is knowledgeable in astronomy, and presumably this writer knows that the creation event really was NOT an explosion. Yet, he/she persisted in using an incorrect term, presumably because “explosion” sounds more dramatic and exciting than “the beginning of expansion of space and time.” And, to be somewhat fair, it is pretty difficult to illustrate the event, so artists just keep on building these flashy explosions and point to them as what the Big Bang might have been like. It may be easy, but it’s not quite correct.

So, what was the Big Bang?

The Big Bang was the beginning of the expansion of space and time. Period. Current theories about this era in cosmic history says little about what was going on before it occurred, although that Pre-BB time is also a time of intense interest to astrophysicists and cosmologists (scientists who study the physics of the cosmos and its origins).

In a sense, we are still inside the creation event of the universe, being carried along as space expands and the cosmic clock ticks along as it has been doing since T=zero. It’s a story that has taken more 13.7 billion years to unfold, and is still occurring.

The universe began as a tiny point of space filled with seething energy. That space began to expand, carrying the energy with it. Over time, things began to cool down, and the first particles of matter condensed out of the energy cloud that was being carried along by the expansion of space. Those particles begat atoms, and molecules, and eventually the building blocks of stars and galaxies.

If you want to talk about wonders of the universe, surely its formation from a seething energy “ball” is wondrous. But, more than that, we can actually see flickers from that time in a wash of cool radiation called the Cosmic Microwave Background Radiation.

So, as my third wonder of the universe, I give you a window onto its creation, more than 13.7 billion years agp. Whatever we call it, it’s one of the most intensely interesting topics in astronomy and cosmology today.