Perspective

If we’re the only life in the universe, does that mean we’re significant, or insignificant?

Are we just a mole on the back of the universe’s foot? Or, are we the actual purpose of the universe? Are we the seed, expected to spread out and explore and conquer the universe? Are we the last sentient residents of a now ashen universe, once full of life?

It’s quite unlikely that any of those questions will be answered within the lifespan of any of us currently alive. But it’s even less likely that we will stop trying to answer those questions.

NASA, not long ago, announced the discovery of a solar system, some 40 light-years away, harboring seven “Earth-like” planets. Three are currently thought to orbit in the habitable zone – where liquid water is likely to exist – not too close, nor too far from the sun to allow water to maintain a liquid state.

All things being equal, if life had arisen on one of those planets during the same time frame as on our Earth, and followed the same pattern of evolution and advancement as ours, we would have found them and they would have found us. Or, so it seems.

The problem is time. We think of the search for extraterrestrial life in terms of vast distances. To really understand the chances of finding any (or us being found), you also need to look at the universe in terms of its staggering duration.

Even at a mere 40 light-years away, finding each other wouldn’t be a sure thing. To illustrate that, let’s look at some numbers.

Michael Faraday created a primitive electric generator in 1831. This is an important date, because, even though, his electricity was running through wires, the act of generating electricity creates radio spectrum noise. It wouldn’t have been coherent radio signals, nor would they have been powerful enough to expect that the signals could have been detected anywhere on Earth, let alone, 40 light years away, but 1831 could be called the opening of the window of opportunity for discovery.

As of this writing, that’s 186 years ago. Out of the 100,000 years of humanity and 4.5 billion years that the Earth has been around, the window of possible discovery via electromagnetic means, has been less than 200 years. We’ve been potentially discoverable for a sixth of a percent humanity’s existence, and for 4.13 * 10-6% of the existence of the planet. Those are small windows of opportunity.

It gets even smaller if you consider a reasonable likelihood of discovery. Electric generation came 186 years ago. Morse code was first transmitted wirelessly 131 years ago. That’s when we started deliberately creating coherent radio signals. The first atomic bomb detonations in 1945 created gamma rays, which, if the Earth was pointed in the right direction, would have been easily detectable 40 light-years away. Really high powered AM radio transmissions started near that time, as well.

On the receiving end, radio astronomy began in the 1930s and we started looking for gamma rays of non-terrestrial origin in 1967. We’ve been looking for radio signals from space for 85 years, and gamma ray bursts for 50 years. Assuming a similar progression on a planet 40 light years away, our 85 years of searching would need to line up with their 131 years of transmitting wireless radio.

You might say that, if they evolved and developed faster than we did, they might have been searching their skies for hundreds, perhaps even thousands of years. Assuming no extinction level asteroid strikes, globally devastating nuclear wars, or climate destroying pollution cycles, our 131 years would need to fall into that few thousand years, out of billions of possible years, which is still pretty unlikely.

For us to have detected the signs of life (coherent radio or gamma rays) on one of these three of seven planets thought to have liquid water, the alignment of advancement would have to be incredibly convenient.

They would have to have advanced to the point of emitting those radiological signs of life, and we would have had to have been listening to the right area of space sometime within the last 85 years. 85 out of 4.5 billion.

That doesn’t help in terms of deciding if we are important, or not. But, it does help illustrate the difficulty in determining if we are alone or not.

The expanding universe – Food for thought

As divisive and self-important as humanity sometimes gets, the universe just keeps moving around us. Hate and fear race across the page, and yet LIGO observes gravity waves, Space-X lands rockets, and 3D printers learn to print replacement organs. We are all really very small.

The most widely accepted estimates put the age of the universe at just under 14 billion years. We’ve seen objects out to 13.3 billion light years away, in all directions. That doesn’t mean those most distant objects are 13.3 billion miles away. They were that distance away back when the light we are seeing today was emitted; 13.3 billion years ago.

The universe is expanding, so those objects are now a distance further away, the amount determined based on on the speed at which the universe is expanding. 13.3 billion years ago, the light we are now seeing started off toward us. While the light has been moving from the point of origin toward us at 186,000 miles per second, the objects have been moving away from the same point of origin, in the opposite direction.

The current school of thought on the rate of expansion puts those observed objects at 46 billion light years away, as of this writing. That means that, in the 13.3 billion years since the big-bang, some amount of matter has traveled as far as 46 billion light years. If true, this brings to mind a paradox: if nothing can travel faster than the speed of light, how did those galaxies get further away from us than the speed of light would allow?

The answer is interesting, and non-intuitive. The expansion is equal in all directions and from all points of perspective that we can observe; we can see just as far in any direction. The only way this is possible is if there is not a center of the universe anywhere within the area we can observe, and if “explosion”, in the conventional sense, is really not the right term to use to describe the big bang. Think of “big bang” as a name or label, not a descriptive term.

In an explosion, everything does start in one place and expand out from that point. Heavier parts move slower, but go farther. Lighter parts initially expand out faster, but lose the momentum battle to air resistance and don’t go as far. During the active time of the explosion, it’s denser near the center, and less dense near the outside edge. Following the active time of the explosion, there is no longer any explosive material, so the center area empties out, becoming hollow, with an inside front moving outwards at a speed slower than the outside front.

That’s not what’s happening in our universe. The matter isn’t expanding away from a center point. Space, the carrier, the “fabric” of our universe, is expanding and taking the matter with it.

One way to visualize this is to take a rubber band and poke thumbtacks into it, equal distance apart, all around it. The rubber band represents the fabric of the universe, and the thumbtacks represent galaxies. You can stretch the band in any direction, and all of the tacks will move away from each other equally.

The carrier, the rubber band, is expanding, and the dots are moving with it. The same thing will happen no matter where you pull on the rubber band, so no point can be clearly identified as the center of your rubber band universe. The tacks, however, are not changing in size. In the rubber band model, the tacks are galaxies, which are bound and contained by gravity (or maybe dark matter), and thus not expanding internally with space.

The objects aren’t moving relative to a center. Space is expanding. Just as the thumb tack does not change spots on the rubber band, the distant galaxies don’t change spots in the fabric of space. The light from those galaxies, however, can still only travel at 186,000 miles per second. Any light from galaxies that were outside of our viewing range 13.8 billion years ago will never reach us. In fact, if the rate of expansion of space keeps increasing, earth bound observers will gradually be able to see a smaller and smaller portion of the universe.

Galaxies are moving relative to each other, but not as the primary method of expansion. It’s more difficult to wrap one’s head around this in three dimensions, and this example is quite simplified, but it’s about as representative as we can get without a lot of math that I don’t have in my head.

Back to your regularly scheduled negative news.