When we see a galaxy being born, we are viewing several jaw-dropping phenomena all at once:
- We are seeing an event that started transmitting light outwards from its location some number of light-years ago; before it got here (and all of the other places it went), there was nothing for us to see in that bit of space
- We are seeing the birth and evolution of something like 100,000,000,000 (100 billion) stars (± some billions, but who’s counting?!?)
- We are seeing fantastically large clouds of ionized gas light-years across in their own right, glowing with the overwhelming energy that initiated with the generation and evolution of that galaxy, however many light-years ago
- The ionized clouds may or may not eventually condense into new dense forms, thus making yet more stars; all of that energy will turn into a local galactic phenomenon much like our own sun or planets, perhaps larger and more ferocious or smaller and meek
- Somewhere in all of that brilliance of stars and ionized gaseous forms of hydrogen, helium, isotopes thereof, and of heavier elements and their isotopes (not to mention naked bits of sub-atomic stuff zooming around), there may be planets condensing from the astonishing catastrophe that initiated that galaxy, settling into white-hot (ultraviolet-hot! x-ray hot!! gamma ray hot!!!) clouds of dust with poorly defined orbits around the gravity centers closest at hand, then condensing further over time into molten elements (or ultra-cold matter balls), then really hot dust with a metal core (or a big chunk of methane, etc. ice), then something coalescing further into a blisteringly hot (or supremely cold) planet, perhaps with an atmosphere of whatever gases stuck around and got pulled into the new planet’s own gravity
That thing we are witnessing from so far away in light-years once happened here roughly 4.5 billion years ago. As the Milky Way condensed into a circulating system and ionized gases condensed into stars and planets started their lazy ellipsoids around those brand-new gravity centers staggering out towards the edge of each tiny solar system, the system settled down into something wild but that followed more deliberate rules than it had initially. Among the planets formed was our little blue world, although it was once more amorphous than it is today and it wasn’t blue until much later in its evolution. It was brutally hot and as it coalesced, solidified chunks of various sizes plummeted into it at accelerated speeds. There are plenty of these solidified chunks out there crashing into our atmosphere even now; NASA estimates that 100 tons (200,000 pounds) of meteoroids hit our atmosphere each day and burn up. Cornell University astronomer Dr. Lynn Carter estimates that 84,000 meteors with a mass of at least 10 grams (about 2 level teaspoons of table sugar) hit the earth each year. While our galaxy was forming, these processes were far more common. With our telescopes—earth-bound, satellite-based, and outward-bound—we see this happening all the time, although paradoxically long ago.
Space.com has lots of great articles elaborating on these processes. For a brief article and video about the formation of planets in our solar system, go here:
For some information on what our early earth was like, go here:
The wonderful and talented folks at khanacademy.org have a series focused on these processes. Here’s the first in a series of five video units.
Inevitably, there are varying hypotheses and timelines associated with exactly how our galaxy, solar system, star (the Sun), and planet came into existence. Is there variation among the hypotheses? Sure. That’s part of the scientific method. Will we ever be able to go back in time over 4.5 billion years and watch the process happening for the next 4.5 billion years? Highly unlikely (in fact, absurd, but it would be the only way to know with certainty; can you imagine being part of a (1) backwards time travel expedition that (2) was stationed somewhere in our portion of the Milky Way to watch, over billions of years, how the process actually progressed?). What we are left with is an enormous data set collected by telescopes that cover every portion of the electromagnetic spectrum scanning the inner, middle, and outer fringes of all the space that surrounds us, trying to watch how it all works. The following is an animated model of how a starburst galaxy forms based on data collected relatively recently by the Hubble Space Telescope’s Advanced Camera for Surveys. This particular galaxy is “only” 300 million light-years from the Hubble.
To close, Hubble has gathered so many images of the universe and of galaxies surrounding our own that its earthly handlers at NASA were able to put together a composite video of our nearest galactic neighbor—Andromeda. It is “only” 2.5 million light-years away—spittin’ distance—just over yonder, etc. Watch this astonishing video composite; it is available in resolutions up to 4K HD, so set your YouTube gear to the highest resolution your video card and monitor can handle and prepare to lose your mind! Each point of light is AT LEAST one star; we cannot be absolutely sure as the point resolution this far from (this close to) Andromeda cannot provide certainty.
And here’s a logarithm-based (our solar system in the center and distances out from our solar system scaled logarithmically) image of the entire known created from NASA data by artist Pablo Carlos Budassi:
Every day, we can view this celestial wonder and try to comprehend its complexity. For me, it is preferable to know that humankind is unlikely to ever understand even a small fraction of this profundity than it is to dismiss it as something comprehended and explained away by oral traditions conceived well over 5,000 years ago and eventually written down and codified as the single explanation to life, the universe, and everything.
With apologies to actual astronomers everywhere.