Search for life beyond Earth; part 1 of tour of the universe

The Eerie Silence

4/7/17

I’m rereading The Eerie Silence. Though I tried my best with it, I thought that maybe there were some concepts I had not understood well enough, and I wanted to go over some things which I couldn’t remember. That’s sort of a shame, my memory limits. Today in chemistry class I came across some problems in which I had to identify whether certain chemical formulas were formulas of acids or bases, according to the products they formed when reacting with water. When I tried to write the end of the chemical reaction equation, I realized I had forgotten the method. I knew how to do it once, and I was good at it, but here I was in the classroom, all those memories gone. I felt frustration and anger because I didn’t want to let my teacher down, and because I didn’t want to reread chapters again–not because I wasn’t inclined to, but because there was no time. I haven’t remembered how to predict the products of chemical reactions since, though I found a way to complete the problems. Anyway, I wish I had better long-term memory. Maybe there’s some way I can improve my long-term memory, because it’s sad to me that I learn important things but lose all that I worked hard to understand when I don’t practice it for a while.

Anyway, I don’t mind rereading the book because it was interesting. This time I want to take notes, analyze, take my time. Before, when I read the book it was to learn, to stuff myself with knowledge. Not to enjoy.

Frank Drake pioneered SETI, the scientific Search for Extraterrestrial Intelligence. The Eerie Silence was written by Paul Davies, who is the chair of a committee within SETI, and the nonfiction book explains SETI’s mission and the likelihood of there being life elsewhere. Davies says “the consequences of success would be truly momentous, having a greater impact on humanity than the discoveries of Copernicus, Darwin and Einstein put together” (2). The title of the book addresses what scientists have so far been met with–a silence, a lack of evidence for extraterrestrial intelligence.

While at the end of the book, Davies reaches the conclusion that “we are probably the only intelligent beings in the observable universe” (207), in the beginning he says that, to SETI astronomers, the silence is not surprising given how hard we have not looked in the short time for which we have been searching. We have not even searched all the stars in our own galaxy, of which there are “400 billion… spread over 100,000 light years of space. And there are billions of other galaxies” (2).

Carl Sagan said that being an astronomer made for a humbling experience, and I understand that every time I look out of myself and of my world and am reminded of the sheer enormity of the world outside, and of our seeming insignificance.

4/9/17

Yesterday I didn’t have access to my computer, so when I read The Eerie Silence and Universe (new book!), I took notes on paper.

Davies says astronomers haven’t looked well enough for the silence to be surprising. Then he says that the search is expanding due to technological improvements. At the time of his writing, construction of 350 radio dishes (known as the Allen Telescope Array) had begun in California. This would broaden the area of sky being searched. In addition, data-processing speed is improving, and scientific instruments are becoming increasingly efficient.

Davies goes on to describe the possible scene if an alien signal were to be discovered. Computer algorithms have been designed to separate space’s background noise from unusual signals, though if astronomers took notice of an unusual signal, it could still be a false alarm. Frank Drake, whom I already mentioned and who still works with SETI today, picked up on an artificial signal that seemed to come from space in 1960. However, after a few simple checks, he discovered that the signal originated from Earth, and was produced by a “secret military radar establishment” (2). In other words, it was a false alarm. That was not the last time there would be a false alarm, and so astronomers must perform a number of checks before they can conclude the signal is indeed of intelligent alien origin.

The first thing this hypothetical astronomer does, according to Davies, is move the telescope off target, and then return it to where it was before, when it picked up on the signal. There are different kinds of telescopes: some are optical telescopes, some are radio telescopes. Here is what a radio telescope might look like:

(I remember being confused a while back, when I first picked up this book, because I had the notion that all telescopes were optical.)

After verifying that the signal’s source is in a fixed location, this astronomer then phones a companion observatory, and another astronomer there checks using the 1st astronomer’s coordinates. She receives the same signal. Davies doesn’t explain the other checks that would have to be performed, but in imagining this scenario, questions arise. You wonder who would be told first, and whether the signal would be meant for us, or meant for someone else, and we happened to be in the line of communication. You wonder whether the signal would contain a message for us that we would be able to decipher, and what information the message would contain. You wonder how the knowledge that we are not alone would affect us. Remember, Davies said it would be a more revolutionary discovery than those of Darwin, Copernicus, and Einstein.

“How and by whom would [the alien signal] be evaluated? How would the public get to learn about it? Would there be social unrest, even panic? What would governments do? How would the world’s leaders react? Would the news be regarded with fear of wonderment? And in the longer term, what would it mean for our society, our sense of identity, our science, technology, and religions?” (4)

Davies later provides his answers to these questions (these answers to these questions are debatable). There’s no doubt that if we received new scientific information through messages from ETI (extraterrestrial intelligence), that would change our ideas and our society. Whenever scientific advancements have been made, both of these have been changed.

The movie Contact, based on a book by Carl Sagan, shows one way things could have occurred, though its events (following the detection of the alien signal) are made possible by wormhole space travel and other things which are speculative. (That’s not a criticism.) However, we don’t know exactly what would happen if an alien signal was detected. There is fortunately a committee within SETI—called the SETI Post-Detection Taskgroup—which was created to address this issue exactly. This is the committee of which Davies is the Chair. As he puts it, “the rationale is that once a signal from an alien source is confirmed, things would move too fast for the scientific community to deliberate wisely” (4-5).

Universe

Now I’m moving from Davies’ book to another, called Universe, which I found in my parents’ collection.

We inhabit the Milky Way Galaxy. When looking up at the night sky, eyes unaided, all the stars we see are ones within this galaxy. The Milky Way is 100,000 light years across—that is, to cross the galaxy, light (fastest thing in the universe) would have to travel (at its ever-constant speed) would take 100,000 years. The universe is expanding, and the billions of galaxies seen by large-enough telescopes are moving apart from each other. This fits with the Big Bang theory.

To give you a taste of the incredible speed of light, it only takes 1.3 seconds to travel between the Earth and our moon. The moon is 1.3 light seconds away from us. Speaking of the moon, a total solar eclipse looks like this. It’s where the moon covers the Sun, and at this time, you may notice solar flares. Solar flares are eruptions of magnetic energy in the Sun’s atmosphere, where radiation is released into space across the electromagnetic spectrum (which I’ve mentioned before). Gamma rays and x-rays are two examples of short-wave radiation released, while radio waves are an example of the radiation released on the long-wave end of the spectrum. Solar flares cause disturbances in the Earth’s atmosphere.

I’m not too informed on this, but I’ve heard something about one needing special glasses to gaze upon a solar eclipse. Don’t just look at one without verifying this—I’m guessing that, even with the Sun largely covered up, one can still gain eye damage from looking at its red outline with the naked eye:

I’ve never seen a solar eclipse, but it seems to be a pretty cool event to watch. Now check out this solar flare, captured on camera during one such eclipse:

Solar flares occur at all times—not just during solar eclipses. When the Sun isn’t obscured, however, it appears to the naked eye (though you should NOT gaze upon it) as a perfect, golden disk:

The solar wind is a stream of particles (originating from the Sun) emitted into space from regions of low-density gas. These regions exist in the Sun’s ultra-hot corona. The Sun’s corona can be easily seen during a solar eclipse. Other stars also have coronas, which are gaseous, enveloping auras.

You see that orange atmosphere around the sun, peeking out from behind the darkened moon? That’s the Sun’s corona:

To be continued.

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s