Tycho Brahe observing the 1572 supernova, with astonished
spectators.
What's that up in the sky? A… uh… an… uh…. Golly, never seen that before…

Ever seen one of those? I won't say UFO, because that immediately conjures images of flying saucers and big-eyed space aliens, and that's not what I’m going for here. What I mean is, have you ever seen something in the night sky that you have "never seen before," but that you later learned was actually a natural and recurring apparition, like the appearance of Venus as the Evening Star?

This time of year usually stirs up a phone call or email or two involving "first time" sightings of the bright star Sirius, whose brilliant, multi-colored twinkling catches some people's attention at least once in their lives, causing them to gawk and either wonder why they'd never noticed it before, or assume it's a new thing in the sky, some rare and unusual occurrence.

Sirius did the same thing to me when I was in Junior High. I walked outside one night, looked up, and saw this glittering spectral jewel, brighter than I could remember any star I'd seen. This hook, or teaser, inevitably led me into the adventure of star gazing, because I had to find out what that thing was. But this kind of "revelation" can happen to people much later in life– and in hind sight I'm amazed I hadn't noticed it when I was even younger.

For the past few months, Venus has been in the western sky as the Evening Star– so naturally I’ve been getting more calls than usual. A man who I would guess (by his voice) was past middle age called to report the brilliant white light in the western evening sky, and was stunned to find out it was Venus. I could hear the amazement in his voice that he had never before noticed Venus in his life, after I told him that Venus comes and goes, alternately from the evening and morning skies, but comes back regularly.

And finally I've reached the "point" of this blog: how we can go through sometimes decades of our lives without noticing, or fully registering, something of unusual beauty that has more or less been "in plain sight" all along (or periodically, at least).

My feeling is that is must have a little to do with timing, a little to do with prevailing conditions in our lives, and a lot to do with how we focus our attention on the world around us, or above us. One day we might look to the evening sky and see brilliant Venus flashing over the horizon and not see anything unusual; twenty years later we might look at essentially the same scene and all of our attention and wonder is suddenly drawn to that inexplicably bright light.

See what you think. Go outside one evening in March, look to the south and see if you can spot Sirius– it'll be to the left of Orion's Belt, if you can find that. And, if you're reading this anytime before, say, March 20th, look to the west after sunset and look for Venus. Maybe you've seen these objects before, and know exactly what I'm talking about. Or, maybe, you'll experience something for the first time in your life. Worth a try, isn't it?

Mark your calendars for March 16 through 28. Don't ask why, yet. Now, read on….

Composite image showing centers of urban light emission
Credit: NASAWant a chance to do some "citizen" science, contribute to an international investigation, and have some fun to boot? An opportunity is coming up in March: Globe At Night. All you need is your eyes….

The problem is summed up in two words: light pollution. A good deal of light produced by human civilization–streetlights, porch lights, shopping malls, security lighting, night time work lights, store fronts, parking lot lights, billboards, neon signs, the list is lengthy–shines or reflects upward into the atmosphere, there scattering off of suspended particles, like dust grains, water droplets, ice crystals and the like.

The scattered light shines back down from the sky, and we see it as a dull nocturnal glow, sometime faint, and sometimes quite pronounced. The amount of scattering particles in the air has an effect on the brightness of the night sky, but the root of the matter is the amount of light sources whose light escapes upward. The closer you are to the heart of an urban area, the more light pollution you will be subjected to.

So what? What's so harmful about that sky glow? Sometimes it can even look kind of pretty….

Well, the fact is, if you've never seen a clear night sky far from sources of major light pollution, you may not appreciate what you're missing: the sight of a clear and dark night sky in which you can literally see thousands of stars. And if you have seen a pristinely dark night sky before, think about the fact that, in 2008, half the population of the Earth was living in cities, many of whom may never have been out of their urban worlds, and for whom the night sky is naturally a dull version of day with a handful of washed out stars above.

There are also effects of light pollution on wildlife that include disturbance of day/night sleep cycles, less cover of darkness from predators, and even effects on plant life.

Globe At Night is a program that's been going on for a few years now whose aim is to measure and monitor the varying levels of light pollution around the world by using individual people as the instruments of measurement.

And it's pretty simple to participate in. The idea is that the brighter the light pollution is in any given location, the few stars you can see. The faintest stars quickly become drowned out in the sky glow, leaving only the brighter ones for your eyes to pick out. All you have to do is go outside on one or more nights in the last half of March, find the constellation Orion (which is pretty easy to find, even in a city), and count the number of stars you see there. Then, report your count through the Globe At Night website, where you'll also be able to see the observations of everyone else around the world, as well as find full instructions for participating.

Now, calendars marked? Know where Orion is? Have a sweater handy? You're all set….

Depiction of Galileo demonstrating his astronomical telescope.2009 has been designated the International Year of Astronomy (IYA), in celebration of the 400th anniversary of Galileo first pointing the new invention of the telescope at the sky.

(Almost as famous as this act of opening our eyes to wonders we'd never witnessed, Galileo was tried by the Inquisition for pointing out that there were more things in heaven than were imagined by Church doctrine–but that's another story altogether…)

It's an intriguing fact that, beyond the Sun merely being a bright disk, the Moon a not-so-bright and slightly mottled disk, the stars pinpoints of light and the planets pinpoints of light that move, everything we have learned about the universe and the objects in it we have learned in the last four centuries, since the invention of the telescope and Galileo's putting it to it's most famous use: astronomy.

Galileo saw on the Moon craters, mountains, and valleys, and likened the "uneven, rough… depressions and bulges" to Earth's geographical features. Venus was revealed to undergo lunar-like phases, which provided controversial insight into the layout of the Solar System. Jupiter had four small "star-like" moons that moved around it–which defied Church doctrine holding that everything in the universe goes around the Earth. And Saturn possessed jug-handle-like protrusions, whatever those were!

It may be difficult to imagine what Galileo was feeling when he made these discoveries of things we take for granted. How exciting to peer through that celestial peephole and discover that the Moon is another world, and that there are worlds out there that had never been seen or imagined before. Sure, new discoveries about Mars keep rolling in, and we're finding a new extrasolar planet about every month–but the excitement about these discoveries is tempered by the fact that we already suspected things like these as possibilities. For Galileo, the magnified astronomical sky was practically a blank canvass.

Back to IYA 2009–what's going on? Who's promoting this, and what is being done to celebrate?

NASA is promoting it, and many different organizations (including Chabot and the Eastbay Astronomical Society) are participating in a number of ways: star parties, special programs, special events, and good old fashioned put-your-eye-to-this-telescope-and-gawk public observing activities.
Honestly, there's nothing like looking through a telescope–and it doesn't have to be a large one. I don't doubt that I first became inspired into astronomy when, as a child, my family would take me to Chabot Observatory to look through the telescopes.

When the new Chabot Space & Science Center reopened the telescopes after the move to our present site, I found all of the childhood wonder flooded back when I put my eye to the eyepiece to regard Saturn. There's an excitement that simply can't be achieved by looking at photographs. You just have to experience it for yourself, as Galileo did four centuries ago…

Are there more actually more stars in the sky, than there are
grains of sand on all the world's beaches?
I think most of us have heard that perennial estimate of the number of stars in the Universe being greater than all of the grains of sand in all of Earth’s beaches.

Sitting on Limantour Beach at Point Reyes awhile back, watching the waves slosh in and out, listening to gulls and feeling very lazy, I found myself looking about me at all that sand, and wondering how it could possibly be true. Reaching out, scooping up a mere handful of grains and letting–what?–a few hundred thousand of the would-be star proxies fall through my fingers, the notion seemed even more absurd.

Raising my eyes from the bit of the cosmos cupped in my hand and taking in the comparatively vast reaches of sand about me–a hundred or so feet between me and the waves, at least a mile or two of beach visible to the north, another stretch to the south, and who knows how many feet of depth beneath the surface? I simply couldn’t believe it. So, I pulled out my journal and started to write down some figures, working out the problem rationally.

So, is it true? Well, here's what I came up with:

Stars: Astronomers have estimated that there are about 200 billion stars in the Milky Way Galaxy. Galaxies come in many sizes, both much larger and considerably smaller than our home galaxy. I don't know what the average number of stars in each galaxy is, but for the sake of this calculation I chose a conservative 10 billion stars per galaxy. Astronomers have also estimated that there are between 50 billion and 100 billion galaxies in the Universe, based on observations made by the Hubble Space Telescope. Again being conservative, I chose the lower figure of 50 billion. So, with those numbers, I calculate a number of stars in the Universe at 10 billion times 50 billion, or 500 billion billion—or in exponential notation, 5 X 10²⁰.

So how does the number of sand grains in the entire world's beaches stack up against that?

To get to that number, I had to do some estimation. First, pulling some numbers out of the air, I decided that an average sandy beach is 30 meters wide (about 100 feet), and 10 meters deep (about 33 feet). Some beaches are wider, some much less so. I don't imagine that the sand on the average beach is as deep as 10 meters—but I've never taken a shovel and found out, either.

Next, I assume that the average sand grain is a millimeter across, giving it a volume of about a cubic millimeter. With that number, I figure the sand grain density to be 1000³, or one billion, sand grains per cubic meter of beach.

The final piece of the equation–after density, width, and depth–is length: the total length of beach shorelines in the entire world. Here's where I made some serious assumptions. Starting with the total length of shorelines of all continents and islands in the world, I got a figure of 356,000 kilometers from the CIA World Factbook. That's 356 million meters.

Now here's where my estimate becomes truly conservative. In my final calculation, I assumed that all 356 million meters of world coastline consisted of sandy beaches– which is not the case, of course; there are plenty of coastlines that are rocky, pebbly, gravely, ice-covered, or sheer cliffs, all without much, if any, sand.

So what were my results? Well, doing the math, 1 billion grains per cubic meter times a 30 meter beach width times a 10 meter beach depth times a 356 million meter beach length and assuming 100% of the coastlines consist of my hypothetical average beach, I get:

1 billion x 30 x 10 x 356 million x 100% = 1.068 x 10²⁰ grains of sand

Compared to the estimate of stars in the Universe, that's about 5 times as many stars in the Universe as grains of sand in all the beaches in the world! I guess the old adage was not only right, but somewhat of an understatement…

But it's all a thing of scale. I also calculated that there are about 3000 times as many water molecules in a glass of water than there are stars in the Universe…

Sitting in a small, non-descript room in the basement of the Lawrence Berkeley National Lab in Berkeley, physics graduate student Hannah Swift and physicist Saul Perlmutter are searching for supernovae, stars destroyed in huge explosions millions or billions of years ago. (They're looking for ones that exploded billions of years ago). Through a computer hooked up to Hawaii's Keck 2 telescope -– one of the largest in the world –- they are able to follow along as UC Berkeley post-doc Rahman Amanullah, a team member who had traveled to Hawaii a few days earlier, supervises the night's observation.

Their goal is to use a device called a spectrograph to get a spectra of five to eight supernovae. This spectrum is a "photograph" of the light emitted by the supernova and it allows scientists to determine whether they are the type Ia supernovae that are useful for their research. By figuring out how far away these type Ia supernovae are (or "were," since by the time their light reaches us, they have long since vanished) and observing how much the light traveling towards the Earth has shifted towards red wavelengths, they can determine how long ago the star exploded. With this information, they're building a history of the expansion of the universe. The weather in Hawaii is good, and the researchers are forecasting a good "seeing."

It's encouraging and moving to see how young these researchers are. Swift is a twenty-something from Kansas. She's so young that she has always understood the universe to be accelerating, that is, expanding faster and faster. She has never thought that the universe is decelerating, which is what the scientific community believed before 1998, when Perlmutter's team at Lawrence Berkeley National Lab and another team simultaneously reported their findings that the universe is accelerating. When this announcement was made, Swift was in the 8th grade. Perlmutter himself is only in his 40s. When he started his post-doc, he and his colleagues had to beg for time on the big telescopes. That wasn't that long ago: our understanding of the universe has shifted very fast.

A few days later, Swift invites us back to the lab to show us some of the data the researchers gathered during the observation. They obtained spectra for five supernovae – a good night's work. Swift is now in the process of figuring out which of the supernovae are type Ia's. To do this, she's comparing their spectrograms to the spectra of a standard type Ia. Light is a very useful tool because different elements emit light of different wavelengths. Swift shows me the spectrogram for a standard type Ia. It has telltale peaks and valleys that reveal what exploding type Ia supernovae eject when they explode – silicon and cobalt, among other elements.

I wonder what big changes in the way we understand our universe will be commonplace when my one-year-old niece is in her 20s. What new discoveries will we use as points of reference in the coming decades? (Assuming we're hip enough to use astronomical discoveries as points of reference!) Will scientists know by then the nature of dark energy, the now-mysterious "something" that is making the universe accelerate, pushing its fabric apart? Will I be able to preface a comment to my niece with, "When you were little, before we knew what dark energy is…"? And will she be able to reply, "Aunt Gabi, you're so ooold!" I suspect she'll do the latter no matter what.

Watch the "Dark Energy" TV Story online, as well as find additional links and resources. Also don't miss our online photo set.

In 1968, John Dobson started the San Francisco Sidewalk Astronomers with the help of two boys who loved astronomy but couldn’t join an amateur astronomy club in the city because they were too young. So the trio created their own club, carting two homemade telescopes onto Jackson and Broderick Streets and inviting curious passersby to take a look at the craters of the moon, the rings of Saturn, the banded clouds of Jupiter.

Forty years later, the San Francisco Sidewalk Astronomers is still going strong, boasting a web site replete with a monthly star chart, specific for San Francisco, a calendar of monthly amateur astronomy events, a helpful "cheat sheet" of astronomical facts and answers to questions that routinely come up if you set up a telescope on your neighborhood sidewalk, and where to go if you want to borrow, build or donate a telescope.

Another great resource for the budding SF amateur astronomer is the Randall Museum, which hosts star parties, lectures by amateur and professional astronomers and classes for making your own Dobsonian telescope from scratch. The free public lectures at the Randall Museum take place on the third Wednesday of each month, sponsored by the San Francisco Amateur Astronomers.

Since 1952, the San Francisco Amateur Astronomers have been an invaluable resource for stargazers to learn about the choicest observing sites throughout the Bay Area, monthly star parties and make contact with a community of like-minded folks. Be sure to also check out their astrophotography web page, where they have uploaded photos and even videos shot with their telescopes of galaxies, comets, moons, planets and nebulae.

If you can't get enough of amateur astronomy clubs in the Bay Area, check out the Astronomical Society of the Pacific and the Astronomical Association of Northern California. The Astronomical Society of the Pacific, founded in the 19th century, has members from 70 countries and claims to be the largest astronomy society in the world. It also boasts educational outreach programs, such as Astronomy from the Ground Up, a National Science Foundation-funded program that helps informal science educators such as docents and volunteers by giving them the tools and training to more effectively communicate astronomy information to the public.

If you should need to buy equipment or talk with some very knowledgeable folks about the right telescope, accessories or CCD digital camera to begin your foray into astrophotography, check out Scope City, a retailer in San Francisco specializing in telescopes and binoculars.

Watch the "Amateur Astonomers" TV Story online, as well as find additional links and resources.


Sheraz Sadiq is an Associate Producer for QUEST on KQED Television.