Star Tales

What DO They Do?

Orion constellation

I want to put my planetarium hat on here and talk about star talks. You may, if you go to the planetarium regularly (or even if you went to one in the past) have heard a star talk. In the trade, we call them the “green arrow shows” because the presenters used to (and some still do) chase stars around the sky with a green-arrow flashlight while pointing out the stars and constellations. Nowadays, we also use red pointers, or sometimes a mouse arrow if we’re using a digital system. Star talks can be done live (with a living, breathing person doing the talking “in the moment”) or as a pre-recorded presentation. Either way is effective.

These shows are a staple of star theater repertory. If you’re a good story teller and can bring the stars alive with some flair and elegance, chances are your audiences will come away having learned a little bit about the night sky and some memorable legends.

So Easy Even a Cave Person Can Do It

Now, people have been telling stories about the night sky ever since the first cave person stepped outside, looked up, and saw those little twinkling lights in the sky and tried to explain them to the rest of the clan. Over the millennia, all kinds of star tales and legends and lore have sprung up. And, many of those stories get told around the planetarium campfire each day, ranging from the ancient Greek myths, which may be based (in part or at least in spirit) on older Mesopotamian myths and legends. There are also Egyptian legends, Native American legends, many flavors of Asian star lore, as well as African tales, and stories of the Australian, South American, Inuit, and Pacific Islands peoples.

Instant Diversity

There’s a lot of interest in these tales for a number of reasons. First, they have many similarities while at the same time have different flavors that come from the different cultures where they were hatched. Second, they often tell stories with morals or important teaching and social goals (sort of like the way fairy tales teach important lessons cloaked in fantasy). Third, they allow a sort of “instant diversity” in the dome, allowing an astute storyteller to bring a lot of cultural material to help teach important science lessons about observation, patterns in the sky, and seasonal change in the skies.

The Good, the Bad, the Ugly

So, is there a down side to these talks? Not in talking about the stars. I encourage star talks, whether live or recorded. Knowing the night sky used to be a survival skill; now it’s part of what makes a human well-educated, whether he or she uses them to survive or simply know more about the universe.

I do think there is a danger of trying to do too much in a given star talk. Why do I say that? Because the night sky, a resource that is NOT available to all people equally, given the vicissitudes of light pollution, lousy weather, or lack of access, can be a bit overwhelming the first time someone looks at it. The first thing you think is “Wow, so many stars!” And your mind tries to make sense of what you’re seeing.

The key is simplification: simply tell people about what they’re actually seeing in the sky. Help them learn THAT before inundating them with half a dozen or a dozen cultural myths that aren’t well illustrated by what you’re actually seeing in the sky.

Look, the starry night is beautiful all on its own. There’s nothing like stepping outside and just confronting the stars, letting them shed their light onto your retinas. And, if you watch long enough, you start to see patterns in the stars. THOSE are the first things that a star talk should address. HOW to find one’s way among the stars and recognize Betelgeuse or Orion or the Big Dipper or Vega or the Andromeda Galaxy or any of the hundreds of other celestial delights that are up there.

After you get through the basics, and people are clear about how to find their way around, then yeah… let’s bring on the cultural street theater of the stars. Those are fun stories and I love reading them all. But they’re not the first thing I would choose to tell people in a star talk. I want them to know the stars first, without the cultural trappings, before moving on to the legendary aspects of humanity’s perceptions of the night sky.

The Science of Life

What Came First?

Yesterday I was at an all-day symposium about the Origins of Life, held by the Radcliffe Institute and the Harvard University Origins of Life Initiative. The keynote speakers covered some of the major bases in a very complex field of play and I came away with the notion that there are no “chicken and egg” questions here, only a lot of people wondering which PART of the egg came first.The image “https://i0.wp.com/www.eso.org/public/outreach/press-rel/pr-2008/images/phot-06-08-preview.jpg?resize=397%2C307” cannot be displayed, because it contains errors.

While I was at the meeting, a couple of press releases plopped into my Email box. Both of them were about subjects that come up whenever you talk about origins of life in the universe. The first was from the European Southern Observatory, showing an artistically beautiful set of data from astronomers who have mapped the distribution of material inside a dark nebula called the Corona Australis molecular cloud. Molecular clouds are places where astronomers have found a number of organic molecules needed for the creation of life. They’re also quite dusty, threaded with the metallic minerals that life also needs. So, it stands to reason that such places would be part of the “egg” that we study when we ask questions about how life got started here on Earth. This is because the solar system formed from such a cloud some 5 billion years ago.

The ESO image is actually a composite of near-infrared scans of the cloud made using an instrument sensitive to such wavelengths. Near infrared light helps astronomers probe the insides of such clouds to understand how they form and evolve.

The other press release that landed in my IN box was from the University of California at Santa Cruz and deals with exoplanets, another piece of the “origins of life” egg. These are worlds around other stars, and are places where we hope to find more life in the universe, some day. In particular, the news here is that a new study suggests that a planet similar to Earth (a “terrestrial type”) could be orbiting one of the stars in the Alpha Centauri system, the closest stars to our own. They lie about 4.3 light-years from us, which for celestial neighborhoods, is basically the house next door. If it does exist, might it look like Earth (as shown in this artist’s conception, done by Mark Fisher)? We won’t know until we find it.

Now, the news here is really that the planet MAY be orbiting the star and that astronomers could detect it using techniques that are in use today to look for stars around other planets. The techniques, which came in for some discussion at Radcliffe yesterday, center around using something called the Doppler detection method. It doesn’t image a planet directly because finding something as small as a planet in the glow of a star’s light is quite difficult, if not impossible in many cases. The Doppler method measures the shifts in light that we see coming from a star as a planet orbits around it. The gravitational pull of the planet is just enough to cause the star to wobble, and that affects how it looks through a spectroscope (the instrument used to study the spectra of light coming from objects).

Detecting the wobbles from big planets, what are often called “Jupiter-sized” planets is pretty straightforward because they induce big wobbles. Little planets, like potential Earth-like ones, cause small wobbles. These are harder to detect. But, according to a computer simulation done by the folks at UC-Santa Cruz, it can be done. The two astron0mers who did the study, Gregory Laughlin (of UCSC) and Debra Fischer (of San Francisco State University), are now leading an international program to study Alpha Centauri using the 1.5-meter telescope at Cerro Tololo Inter-American Observatory in Chile. They are hoping to find real planets, based on their simulation and using the technique of Doppler detection.

These two studies are chewy and tasty pieces of the larger pie that is the search for life (and its origins) in the cosmos. It’s only a matter of time before those other planets will be found (if they’re there). We continue to study how life began on our own planet. What we learn should be helpful if and when we ever find life elsewhere in the cosmos.