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About this time each year, I start to get emails about what to give somebody who’s “into space” for a holiday gift. Of course, I always recommend books, which are a great way to learn about astronomy and space exploration. So, think about a favorite book YOU enjoyed about space or astronomy, and see if that is still available. Or, browse around the stacks at your favorite bookshop. I recently got a review copy of David Dickinson’s Backyard Astronomer’s Field Guide. It’s a really nicely put-together book for just about any observer. It’s well-written, and is wire-bound to lay flat if you have it with you outside during an observing session. I certainly enjoyed reading it and you or your loved one will, too.

Two observer's handbooks to think about for holiday gifts.

I also got a review copy of a book called 100 Things to See in the Night Sky. It’s by Cincinnati Observatory astronomer Dean Regas. It is what it says on the tin, a guide to a hundred objects you can search out and explore in the sky. It comes with easy to understand explanations about the objects, and also talks about constellations, satellites, meteors, and meteor showers. The book has four sections for the seasons and then goes into detail about other objects.

Moon Rush, by Leonard David; a look at near space exploration. — Learn about lunar exploration past, present, and future.

Also not to be missed is Leonard David’s book called Moon Rush: The New Space Race. With today’s news about various lunar missions, this book is pretty timely. It gives a good look at what’s at stake for the exploration of our nearest neighbor in space.

Leonard’s an old friend and experienced skygazer, as well. He’s a long-time space science writer who was also one of the leads at the National Space Society and has covered nearly every space initiative around the world.

My Own Space Books!

Of course, I have a few books out there, as well. My Astronomy 101 book is doing well and is a perennial favorite. It has 55 chapters (short ones!), each readable in an hour or less. I’ve heard that a lot of teachers use it as a second book in their classes, and I’ve also gotten very nice notes from people who simply like to use it as a way to learn more about astronomy.

My latest book is called The Discovery of the Universe and it came out in the U.S. just as the shutdowns started to happen due to the pandemic. It’s really about observatories and the discoveries in astronomy that they have enabled since — well, really since the dawn of time. There are thousands of observatories around the world, ranging from high-tech professional facilities to simple backyard-type viewing platforms. Some of the facilities I wrote about don’t even look like our preconception of an observatory, such as the IceCube detector array in Antarctica. The book’s full of looks at places like that, and as your humble writer, I’d love it if you got a few copies for yourself and your loved ones to read while you’re still social distancing.

The other book I’ve written recently is called Space Exploration: Past, Present, and Future. It is just what it says on the cover—an exploration of space exploration. It’s written for the folks who want to know a little more about the rockets that keep going up to the Moon and beyond. It begins with a history of the technologies that contributed to our space programs today and includes chapters on space education, outreach, and other space-related cultural activities.

Gifting Astronomy Gear

Every year, I get questions about telescopes or binoculars. I always say the same thing: find out what the person you’re gifting this to wants to observe! If they’re mainly interested in deep-sky objects (nebulae, galaxies, etc.), that’s going to guide your decision. If they just want to do planets, that will also send you in the correct direction. If they want to scan the skies and learn constellations, a good pair of binoculars will do the trick.

Next, don’t cheap out on the purchase. A lot of people will head straight for the cheap department-store scopes or binoculars because, well, they’re cheap. I’ve often heard parents say, “I don’t want to spend a lot of money on something that might end up in the closet.”

That’s understandable. If it’s going to be a problem, then maybe the young person they’re buying for is too young or not quite mature enough to handle the responsibility of a scope. In those cases, I’ve often recommended binoculars. You can do quite a LOT of stargazing with those. In fact, that’s pretty much all I use these days. (Yes, I’m lusting after a telescope, but am saving up for a really good one.) So, consider a good pair of binoculars, which will probably cost about $100 or so, and look around for those labeled “7 × 50” or “10 × 50”. Anything larger is too difficult to hold steady and you’d need a tripod with a special mounting bracket for binoculars.

Get a Sturdy Gift

If you DO go for a scope, make sure it has a good mount and tripod. There’s nothing more disappointing than a scope on a spindly tripod that won’t even hold the weight of the instrument. And, whatever you do, avoid the department-store scopes. Go to a good camera shop, or go online to places that deal ONLY in telescopes. If you know someone with a scope or know of a local astronomy club, ask them for advice.

At the low end, you can expect to pay under $500 for a good telescope. Astronomers Without Borders is a charitable organization that has a couple of decent beginner scopes for sale under that price. Check them out. And, if you want in-depth information about telescopes. check out Sky & Telescope’s good article about picking out telescopes. It covers a lot of what you need to know.

Accessories for the Stargazer

Of course, there’s also a wealth of accessories you can buy for the stargazer. That includes everything from star wheels and software to warm-weather gear. I’ve always liked those little pocket hand warmers for cold observing nights. A flashlight with a red filter is also a welcome piece of kit. Why red? When you’re out observing, your eyes get dark-adapted. If you turn on a flashlight without a filter, that blasts the dark adaptation. For most folks, it takes 10-30 minutes to get fully dark-adapted. So, a red flashlight is a good choice, too.

Stargazing is, at its heart, a chance to look at the same stars our parents, grandparents, and their grandparents did, and so on back through the generations. The stars you and I see tonight haven’t changed a great deal since the first people began looking at the night sky in a quest for understanding. And, people around the world share the sky. So, not only is it a great gift, it’s a continuation of humanity’s heritage among the stars.

Don’t Forget to Look Up!

This year, without as much of the hustle and bustle of holiday parties and shopping, many of us are staying home or close to home. Sometimes the simplest gift is one of time and access. Take your loved ones out for a good stargazing session. For that, all you have to do is step outside and look up. Sometimes it’s less about the equipment and all the other accouterments, and more about the time you spend with those you care about in life. Here’s an easy sight to get you started; I wrote a blog entry a few years ago about the most obvious sky sight in all our skies—Orion the Hunter. It’s in a part of the sky that contains many gorgeous sights. So, when you get a moment, go out and check it out. It’s absolutely free and will give you a much-needed gift of beauty.

Last week, the SETI Institute put out a study that claimed there could be as many as 300 million potentially habitable worlds in our galaxy. That’s a pretty good number, considering that nearly every star is likely to have (or have had) at least one planet (according to another study). What’s more, given the distribution of stars and planets in the Milky Way, some of those potentially habitable worlds could be fairly close to us. This isn’t just some “pie in the sky” guesstimate. Scientist Jeff Coughlin (of the SETI Institute) and a team of researchers used Kepler Space Telescope data as well as observation sets from the European Space Agency’s GAIA mission to come to their conclusions.

A possibly habitable world, among the 300 million that scientists at SETI institute think exist in the Milky Way Galaxy. — An artist’s conception of Kepler-186f. It’s the first confirmed Earth-size planet found orbiting a distant star in its habitable zone. Credit: NASA Ames/JPL-Caltech/T. Pyle

Estimating the Number of Such Worlds

So, if there ARE 300 million potentially habitable worlds “out there”, what might they be like? Anybody who reads science fiction probably has a good idea. Visiting other planets is a staple of that genre. For those of us who read SF, the existence of worlds with life on them is not a new idea. But, for science to work, there has to be observational data of those worlds. That’s to feed any theories about what these places might be like. To answer the question, and come up with their estimate of 300 million, the SETI team devised a plan.

First, they studied other worlds that are similar in size to Earth. They looked for probably rocky worlds orbiting stars similar to the Sun. (SO, this cuts out rogue planets, which I discussed in my last entry.) And, of course, they wanted planets in the “habitable zone”. That’s where liquid water could exist on the surface of planets orbiting within it. Add in other factors, like how much light hits the planet from its star, and that gives scientists a good set of parameters for estimating how many such worlds exist. But, it still doesn’t tell us what they’re like.

Finding Life on Habitable Worlds

Determining life on distant worlds is not something we can easily figure out from Earth. Well, astronomers can use special techniques to study the atmospheres of those worlds. There are some chemical signatures in atmospheres that would indicate the presence of life. And, of course, one could direct the radio telescopes of the Allen Telescope Array, for example, in their direction, to see if any intelligent civilizations are beaming out signals.

That’s one way beings “out there” could tell if our planet has life, by the way. We’ve been sending signals to space for around a hundred years, from radio and TV broadcasts. They are racing out away from us at the speed of light, and there ARE some potentially habitable worlds within that signal path. (It’s actually an expanding balloon of signals called the “radio sphere”.)

Another way might be to look at our atmosphere as our planet transits the Sun. A distant observer, with direct line of sight to see such an event, would see sunlight streaming through our atmosphere. The gases in our air blanket would absorb specific wavelengths of light. That creates “dropouts” in the solar spectrum. Each element and chemical compound has a specific “fingerprint” that could show up in the spectrum. Those that life emits would clue in a distant researcher that there’s life on our planet.

The Search is Afoot

That is, in fact, what researchers plan to do: study the light from the star as it passes through a nearby planetary atmosphere. If the fingerprints of chemicals related to biotic activity are there, then it’s a likely sign that life exists there. Of course, it’s painstaking work. It isn’t done overnight. It requires detailed observations and a LOT of analysis. That’s the way the science works and such observations are happening.

They will take a while, so while we wait for that first momentous discovery, we can still marvel at the fact that there are 300 million planets out there to study. Some of them just HAVE to have life. We can’t be the only ones in the galaxy looking out and wondering who else is out there. Or, to put it another way, in his book with Ann Druyan, the late Carl Sagan wrote, “The universe is a pretty big place. If it’s just us, it’s just us, seems like an awful waste of space.”

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