Winter Wonderland? Wonder No Longer

Andrew Fraknoi, professor of Astronomy, Foothill College, Los Altos Hills, Calif.

Paul Yeager, writer and meteorologist, author, "Weather Whys. Weather Whys: Facts, Myths, and Oddities," State College, Penn.

David Mizejewski, naturalist, National Wildlife Federation, Reston, Va.

The winter solstice has come and gone, making it officially winter in the U.S., with cooler temperatures, less sunlight, and, in some places, snow, ice, and frost. A panel of experts discusses the different phenomena that combine to make up the season we call winter, and give tips for how best to appreciate the natural world in wintertime.

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IRA FLATOW, HOST:

You're listening to SCIENCE FRIDAY. I'm Ira Flatow. As the song goes, look around, leaves are brown and the sky is a hazy shade of winter. But why? Why do the days get shorter, it gets colder, plants go dormant, animals migrate or hibernate, the constellations change in the sky?

If you've ever wondered about how winter works, give us a call. For what you can see in the skies to what you can spot in your own backyard gardens, we're here to help you see and enjoy the winter wonderland, answer your questions, maybe even make you enjoy it more by knowing more, as Richard Feynman used to talk about.

Our number, 1-800-989-8255 is our number. Our guests are - let me introduce them - Dr. Andrew Fraknoi, he is no stranger to SCIENCE FRIDAY. He's a professor of Astronomy at Foothill College in Los Altos Hills, California. He's at KQED in San Francisco. Welcome back, Andrew.

ANDREW FRAKNOI: Nice to be with you again.

FLATOW: And I saw Orion out for the first time a few weeks ago. I was very happy to see that winter was back.

FRAKNOI: It's true. This is a wonderful time for stargazers.

FLATOW: All right, we'll talk more about that. Paul Yeager is a writer and meteorologist and author of the book "Weather Whys: Facts, Myths, and Oddities," published by Perigee Books. He joins us from State College, Pennsylvania. Welcome, welcome to SCIENCE FRIDAY.

PAUL YEAGER: Good afternoon, how are you?

FLATOW: You're welcome, thanks for joining us.

YEAGER: I'm glad to be here.

FLATOW: So are we. David Mizejewski is a naturalist with the National Wildlife Federation, he's at our headquarters, based at their headquarters in Reston, Virginia. He joins us from our NPR studios in Washington. Welcome to SCIENCE FRIDAY.

DAVID MIZEJEWSKI: Thanks for having me.

FLATOW: Andrew, let me go back to winter. You know, most people have - I talk about this, there have been studies of Harvard graduate students. Why is it hotter in the summer or colder in the winter? And so many people have no idea, do they? They all get it wrong.

FRAKNOI: That's correct. In fact most Americans believe that it's distance from the sun that gives us the hotter and colder days. And actually it's very interesting, because yesterday was what we astronomers call perihelion day, when we were actually closest to the sun, and yet it's winter. So it clearly can't be the distance from the sun that controls the seasons, and we know that in fact the reason for the seasons is that the Earth is tilted.

Like an accident victim whose back is injured and who can't stand up straight, the Earth had an accident many billions of years ago, and the result is that the Earth's axis is permanently tilted, and we go around the sun leaning over. And it's that lean in the Earth that causes the sunlight to differ in the summer and in the winter, that gives us the more spread-out sunlight and gives us the shorter days that characterize our winters in the Northern Hemisphere.

FLATOW: Let's talk about - you talked about the perihelion. What is the solstice? That sort of confuses people, too, doesn't it?

FRAKNOI: Well, that's right, so perihelion means closest to the sun, and solstice is the time when we have the shortest day and the longest night. We had our solstice in December, on December 21, 22, and that's the time when, because of the Earth's axis leaning, we get the longest period of time when we're in darkness and the shortest period of time that we're in the day.

FLATOW: 1-800-989-8255. Paul Yeager, now that we know the difference between and why we have winter versus summer with the planets and the sunfall, what difference in incoming energy accounts for everything we think of as, like, winter weather?

YEAGER: Oh, it makes a huge difference, and everything that Andrew just talked about plays into why cold air breeds during the time of year when the sun is tilted away from the Earth on that particular axis. So right now, the Earth is tilted in such a way that there's almost complete darkness in the northern part of the Northern Hemisphere, perfect breeding ground for cold air.

More energy from the Earth escapes from the Earth than comes in. Therefore, it gets colder, promotes more snow cover. The more snow cover, the colder the ground is, the more the heat goes away, and also the sun - I mean, the snow on the ground also reflects the sunshine away from the Earth, also promoting it to get cold.

FLATOW: Why is it that times we'll have - even here in the Northeast, we're having, I don't want to jinx it, a very mild winter?

YEAGER: Well, yeah, so far this year what's been happening is that we sort of have a northern branch of the jet stream and a southern branch of the jet stream, and the northern branch is the one that's responsible for bringing the cold air southward, and that has stayed pretty far to the north so far this winter season, and it's kept the cold air locked in more across Canada than it has been able to come southward in the United States.

FLATOW: David Mizejewski, people often say oh, winter's so depressing, you look outside, everything is dead, but that's far from the case, is it not?

MIZEJEWSKI: That's absolutely far from the case. You know, in fact winter for me is one of my favorite seasons. You know, one of the coolest things about winter is that there are no leaves, at least not on the deciduous trees, and that makes opportunities to get outside and observe nature, you know, so much greater than maybe in the warm seasons.

You know, you can go bird-watching. You can look for tracks in the snow or even in the mud if there's no snow on the ground, and you just have a much bigger chance of actually getting to see something. And at National Wildlife Federation, that's one of our things that we try to get people to do is actually go outside.

And so winter can be a really great time. You know, you just - if it's cold out, bundle up, head outside. There's tons of great field guides. And if you just observe, you're going to experience some really cool things that you wouldn't get to see otherwise.

FLATOW: Andrew Fraknoi, I mentioned my favorite constellation, Orion, is showing up in the winter. Why do these different constellations have seasons to them?

FRAKNOI: Well, we see, as we go around the sun, we see different constellations at different time of the year. And winter is really good from an astronomer's point of view because we have these long nights, and so you have more of an opportunity, as long as it's not snowing or cloudy, to take a look at the brilliant winter sky.

And you point out probably my favorite constellation, too, which is the constellation of Orion, pretty easy to find because there are two very bright stars that define the shoulder and the leg of this great hunter named Orion from ancient legend.

And then there are three bright stars that make up a belt, and that's pretty easy to spot. And then you can see the brightest star in the sky, Sirius, if you follow the belt along toward the left, and that's a pretty spectacular constellation or star grouping that almost everyone can find if you're looking in the winter sky.

FLATOW: 1-800-989-8255. Let's see if we can get some phone calls in here from lots of inquisitive people. Carl(ph) in Buffalo, New York, hi, Carl.

CARL: Hello, hello, great show as always. Everybody loves the weekend for certain reasons, obviously, but I like it because of SCIENCE FRIDAY. I look forward to the show every week.

FLATOW: Thank you.

CARL: So keep up the great work. Two things: There's a strange phenomenon that happens in Buffalo, New York, surrounded by Lake Erie. In the summer, clouds are like any other city, they're overhead, they're everywhere. But in the winter, they surround the city, a real thick cloud just surrounds the perimeter of the city. It's only maybe about 10 degrees above the horizon. It's a very strange phenomena. I was wondering if you knew the answer to that.

And also one more quick question, the back-to-back La Ninas, why is this year's La Nina so much different than last year's?

FLATOW: All right, Carl, thanks for calling from Buffalo, always has a special place in my heart. Paul, got any answer for that?

YEAGER: Well, I'm guessing the clouds have to do with the difference in the temperatures of the lake. During the summertime, the lake is cool relative to the air masses around it, and during the winter, the water is, until it freezes, relatively warm compared to the air masses around it, and that probably is what makes a difference in where the clouds form, just as it makes a difference in when you get lake-effect snow and things like that.

And as far as the La Nina, you're absolutely right. There is a La Nina this winter, and there was a La Nina last winter, but the two winters have so far been dramatically different. And one of the reasons for that is, you know, La Nina and El Nino are two things that are often talked about by meteorologists and by the general public because they're pretty well-understood.

They affect the climate pretty dramatically in a given year. So they tend to be the first things we think of. However, there are other atmospheric phenomena that can supersede a La Nina or an El Nino in a given year. And this year compared to last year, there has not been as much of a negative phase of what's called the Arctic oscillation, which is something that allows that cold air to come southward out of Canada very effectively in the eastern United States.

FLATOW: 1-800-989-8255 is our number. Lots of folks want to ask good questions, like Cathy(ph) in North Carolina. Hi, Cathy.

CATHY: Hey, how's it going?

FLATOW: Hey there.

CATHY: Great. This is just something that the logic has always escaped me. All right, the winter solstice, December 21st, that's when the angle is - you know, we're leaning the most, and those rays are the shortest. Then why is it that January and February are just about invariably the coldest months? Shouldn't it be like January and November, peaking in December, and February is comparable to, say October?

FLATOW: Good question, Cathy.

YEAGER: There is a bit of a delay in what happens, you know, when you get the lack of sunshine for - until the atmosphere actually cools, so its coolest point is like a one-month delay. It is the same thing when you're at your maximum amount of sun coming in during the summer. There's like a month delay until the atmosphere warms to its warmest. So there is always a little bit of a lag with your normal temperatures being a month behind, you know, the astronomical phenomena.

FRAKNOI: Ira, if I can add...

FLATOW: Go ahead, please.

CATHY: OK, though, can I possibly (unintelligible) question...

FRAKNOI: Did you experience the same thing...

FLATOW: What's that?

FRAKNOI: Hold on one sec.

FLATOW: Hang on. Let Andrew finish up the answer.

CATHY: Oh, I'm sorry. I'm sorry.

FRAKNOI: So the - you notice the same thing in your swimming pool, right, that your swimming pool doesn't heat up right away. Much of the Earth's surface is made of water, and it takes a while for the heat to be lost in winter and to be gained in the summer. We call this the seasonal lag, and that's why you'll notice that the hottest days of the summer are not at the summer solstice, but a month or two after that.

FLATOW: Yeah, that's why Buffalo is getting all that snow because the warm water is all evaporating. Its cold air just over it and pounds it. Yeah, I'm sorry, Cathy, you wanted to say something else?

CATHY: Yeah, just one other quick question. I'm up in the mountains in the northwestern North Carolina. And we have an interesting little phenomenon here that in the winter, we'd had next to no snow this year so far. But when we do get snow, sometimes there will be not a cloud to be seen, but there's still snow coming down, just a very fine snow, but there's - you look up in the sky and there ain't no clouds up there.

FLATOW: So is it like sort of a fine, misty snow or...

CATHY: Just a very fine, so fine snow. And you're kind of looking around and it's not windy, and you're saying, well, OK, where is this coming from.

FLATOW: Paul, do you have a suggestion for that?

YEAGER: Well, you know, you usually - to have official snow falling from the sky, you are going to need to have some form of clouds. You know, what might be happening is it could be some version of a fog that's kind of freezing into ice crystals close to the ground. You know, you might be able to see the sun through something like that. But, you know, for you to have real snow falling that's accumulating an inch at a time, something like that, you would need to have, you know, legitimate cloud.

FLATOW: Thank you, Cathy.

CATHY: No - OK, thanks. Bye-bye.

FLATOW: Take care. Did you want to jump in there, say something? Whom did I interrupt? No one, I guess. 1-800-989-8255 is our number. we're talking about what goes on in the wintertime. And we're talking about snow. And another thing people think about when they think about winter, Dave, is animal hibernation.

MIZEJEWSKI: That's right, yeah. And, you know, the whole idea of what wildlife does in the winter is actually really tied to what we were just talking about, and that is not necessarily temperature. I think a lot of people think, oh, it's getting cold, you know, so the trees are losing their leaves and, you know, the birds are flying South, and the bears are going into their winter sleep. It really has a lot more to do with photoperiod, with the amount of light. That really is the trigger in the behavior of these living organisms. And it's kind of neat to think about the fact that, you know, these plants and animals that live on the surface of the planet, along with us that we see every day really are being influenced by, you know, by the much bigger, you know, what goes on with the sun and the axis of the Earth and everything.

And it's a macro way of think about all this. But, yeah, hibernation or winter torpor is something that a lot of species do, and it's just their mechanism of surviving the fact that there is a lot less sunlight, which means that plants can't photosynthesize as much, if at all. And that means that that there's a lot less food at the bottom of the food chain for the, you know, the smaller animals and the herbivores to actually, you know, eat and then higher up the food chain, the predatory, carnivorous animals don't have anything to eat. So what a lot of animals do is they just sleep it off.

FLATOW: Sleep it off.

MIZEJEWSKI: Bears will go into dens. They don't do a true hibernation. Their body temperature doesn't get really low like the true hibernators, like, some of the ground squirrels or the bats or reptiles and amphibians. But they pretty much, you know, they sleep away those cold, lean times. And when the sunlight - the amounts of sunlight start increasing and the plants are able to photosynthesize and the insects wake up and start reproducing. And again from that base of the food chain, the animals that sleep through the winter wake back up. Similarly, another strategy for survival is migration. You know, everybody knows that birds migrate south for the winter. And not all birds do, obviously, but a lot of other creatures do too, including butterflies - monarch butterflies make an immense migration from, you know, as far north as southern Canada, all the way down into Mexico every year.

FLATOW: All right. Let me just remind everybody that I'm Ira Flatow, and this is SCIENCE FRIDAY from NPR, and talking about things to see in the wintertime with Andrew Fraknoi, Paul Yeager and David...

MIZEJEWSKI: Mizejewski.

FLATOW: Thank you. Mizejewski. Somebody says, how do I get these names right. You see, I don't. 1-800-989-8255 is our number. Lots of people are talking about the winter, let's - in the couple of minutes before the break, let's go to someone who knows a lot about winter. Mary in Fairbanks. Hi, Mary.

MARY: Hi, Ira. Thanks for the great program. I had to call in today.

FLATOW: Tell us, do you like the winter in Fairbanks?

MARY: Winter is my favorite season. I've lived here for 47 years, and I celebrate the summer solstice because it's starting to get darker and darker and darker and winter is coming. And then by about November, December, we really have much shorter days, about four hours of daylight. But I've learned that you have to live with nature, not try to fight nature. And I've - my strategy for survival is just to adapt to the change and enjoy a more introspective time where life can slow down a little bit, and you can take the time to think about things and read more. And it is a feeling of denning up and then one that - right now, it's getting light about quarter to 9. There's some light in the sky, and you just want to get out in the middle of the day and do things and then stay inside when it's real cold and be comfortable.

FLATOW: So it doesn't depress you at all, all that darkness?

MARY: As long as I can get outside for a couple hours a day, when it is light. That's what I need. And I taught school one year and it drove me crazy because I had to be inside all day long, and I learned that that wasn't the job for me, so I work seven days a week in the summer, and then in the winter I'm more in charge of my time, and I can just go out in the middle of the day and get a good dose of sunshine and enjoy winter.

FLATOW: Wow. What a very nice way to look at it.

MARY: Well, it's - it rules here, and it's a major long season up here. So if you don't like winter, you shouldn't live in Fairbanks, but I love both Fairbanks and the winter.

FLATOW: All right. Thank you very much, and have a joyous winter.

MARY: Thank you very much. I feel blessed to be here.

FLATOW: Thank you for calling. No better call, then, to go to our break. We're going to come back and - after this break and talk lots more about winter with Andrew Fraknoi - he's professor of astronomy at Foothill College in Los Altos Hills, California - Paul Yeager, author of "Weather Whys: Facts, Myths, and Oddities," and David Mizejewski. He is a naturalist with the National Wildlife Federation. Our number: 1-800-989-8255. You can tweet us your ideas about winter, @scifri, and also go to our website at sciencefriday.com and our Facebook page. We'll be right back after this break. Don't go away.

(SOUNDBITE OF MUSIC)

FLATOW: You're listening to SCIENCE FRIDAY. I'm Ira Flatow.

We're talking this hour about winter. And, you know, if you've been following us on our website all week long, we've been hosting a winter photography contest on our Facebook page, and we want your best winter nature shots. We already have about a hundred or so on our Facebook page, but we still want more of them. So you can go to our SciArts page of sciencefriday.com for info on where to send your photo.

We'll take your submissions, oh, up until Sunday night. The instructions are also on our Facebook page. And then we're going to be judging and picking a winner, and we want you to be part of that judging process. Even if you aren't a photographer - you haven't sent us anything - you can go to our Facebook page @scifri and vote for your favorite photo by liking it. Click on that little like button.

And we're going to keep the voting open until next Wednesday at midnight, East Coast time. And the photo with the most likes is going to get the coveted SCIENCE FRIDAY pocket protector, hand-autographed by someone here. So start voting. Send your photos in, and we'll pick a winner by next week and announce it on next week's program.

In the meantime, we're going to still be talking about winter. My guests are Andrew Fraknoi, Paul Yeager and David Mizejewski. Our number is 1-800-989-8255. Let's talk some questions here before we go to the phones. You know, all the time - and I'll just throw this out to the - to general discussion here - if you're from the North like I am and you go to Southern states or other parts in the South, you're wondering, what's winter like to the plants and the animals here? Do they actually experience a seasonal change?

MIZEJEWSKI: Well, yeah. I mean, the - there's a lot of species that have wide range and are found, you know, in the North, to use the U.S., for example, and the Northeast as well and the Southeast. And, you know, sort of the different populations follow the rhythms of nature, right? And so the winters in the Deep South don't get as bad as the winters further North.

And so, for example, you know, to use the bear winter dormancy example, you know, bears might be active a lot longer into the year. And in some places, maybe they don't even go dormant, whereas further North - where, you know, it's darker, the winters are more harsh - maybe they're going to go into dormancy earlier. You also see different species living in those different areas for that exact reason.

You know, there are certain species that can't tolerate a - an extremely cold winter. And so their populations only get as far North as the upper, you know, South or maybe into the Mid-Atlantic. So there's various strategies that living creatures have evolved over thousands and millions of years to survive and kind of, you know, kind of be in this rhythm with what's going on with the axis of the planet and the weather and the seasons and the climate.

FLATOW: Let's go to Ramona(ph) in Norwich, Connecticut. Hi there.

RAMONA: Hi. How are you, gentlemen?

FLATOW: Hi there.

RAMONA: I have a question. I live in the suburban part of Connecticut, and deer often come and eat off my apple trees towards the end of the summer. And, lately, they've been putting in new housing developments around me, and the deer seem to be shoved into the back of my two acres in the wood there. So they come into my yard and eat off my bird feeders. I've begun to be putting the bird food on the ground for them, and apples and pears and things like that. Is that necessarily a bad thing?

MIZEJEWSKI: Well, I'll take that one. You know, generally speaking, we don't recommend any kind of artificial feeding of wildlife beyond maybe putting out a bird feeder for seed-eating birds. You know, there's research out there that shows that the birds typically are only using that as a supplement to the natural food sources, which just highlights why it's important to keep native vegetation around because that's where the birds are getting their natural food sources.

You know, here's the thing with white-tailed deer. You know, they might look like they're cold and they're suffering, but in the bigger picture in terms of their species, they're doing quite well, particularly in the Northeast. And while, you know, you might be tempted to want to go out and help them in the cold, they can survive just fine. And believe it or not, they do really well in suburbia.

You know, this mix of woods and fields and lawns and gardens has actually allowed the white-tailed deer population to explode - that and the fact that we've killed off all the wolves and mountain lions in the Northeast. So it's generally considered not a good thing to artificially feed the deer. It could bolster their populations, and then in the summertime you get deer ticks and all that kind of thing.

FLATOW: Thanks for calling, Ramona.

RAMONA: Thank you.

FLATOW: They're certainly doing OK, the deer on my block. 1-800-989-8255. Let's go back to Palmer, Alaska. Bill in Alaska, hi. Welcome to SCIENCE FRIDAY.

BILL: Yes. Good to hear from you - here anyway. I was just listening to the description of Fairbanks. Palmer is down by Anchorage near the ocean, so we get a lot more clouds and stuff. And so I call it five-and-a-half hours of twilight because the sun never rises in the east and it never rises in the west, except on an equinox.

FLATOW: Wow.

BILL: It goes around in a circle up here. And right now I'm looking out my window, and it's, oh, 15 degrees above the mountains, looking at me. So that's a little different. And one of the big deals I remember we used to do with the kids is star light, star bright, first star I see tonight. And that's sometime in September, because we haven't seen stars all summer long, or the moon. And that was kind of a fun thing. And then of course...

FLATOW: Wow. You know, we never think about that.

BILL: Yeah.

MIZEJEWSKI: Ira, this leads to a more general issue, which I think our listeners will be interested to think about, which is that the seasons are not the same in different parts of the world. We in the United States take things so much for granted, that what we get is what everyone gets. But, for example, right now, when we're having the winter in the Northern Hemisphere, they're having summer in the Southern Hemisphere.

This is summer vacation time. So - and in the same way, as our listener said, sometimes you get these perpetual days of night, where you don't get any daylight at all at high latitudes, or you might get perpetual nighttime or perpetual daytime, depending on where you are, north or south. So this whole idea that our seasons are the only way to be, that's a good thing to get out of your mind and to imagine that there are many ways that people perceive and experience the seasons all around the planet.

BILL: Yes. And that's the problem here psychologically, because if you go by the sun, you've still got another month and a half of so-called spring or something, you know, because the seasons don't change with the angle of the sun like they do in the in the South 48, and that is a noticeable difference if you let it bother you.

FLATOW: You know, Bill - but you have used - you have something in the Northern states and parts of the country and the globe have something that I have never seen that I'd love to see, and you see it more in the winter, and that is the aurora, right?

BILL: Oh, definitely. Definitely. Yeah. It'll stretch from the southern sky to the northern sky, sometimes the whole sky, and dance around and colorful. That's the best part of winter.

FLATOW: Yeah, yeah.

MIZEJEWSKI: That's beautiful...

BILL: But we are noticing the climate change up here quite a bit, and we're getting more precipitation than we have in the last 20 years. Valdez, over there on the coast, is up to - their - they can get 500 inches of snow a year. But - and we've noticed, some of the articles I've read, the vegetation is moving into the tundra area, the (unintelligible) and small bushes and stuff, which they think is because of the warming of the tundra.

The tundra, of course, is permafrost, and some of that's really - and you can spot it if you've looked at a place - a couple pictures where the brush - you know, three, four, five. That makes good (unintelligible). But - and then of course all the erosion along the northwest coast of Alaska that's wiping out the villages because the ice doesn't freeze up to protect them.

FLATOW: Not anymore in the winter. Thank you, Bill, for calling, and have a - and enjoy your winter.

BILL: Thank you.

FLATOW: Take care. Yeah, and another thing that's not happening in winters or, as much as he says, they're not - they're getting more precipitation, and permafrost is not staying over as long as it used to.

MIZEJEWSKI: Yeah. And I'd just to add to that, you know, that's a big issue. You know, climate change obviously is a big issue that National Wildlife Federation is working on and, you know, the scientific community is really watching because one of the things that we're anticipating is wildlife having to, you know, adapt or migrate to deal with the changes in their environment due to this bigger, you know, climate change. And you're seeing it already on the frontlines, you know, places like the tundra where some of the woody plants are moving northward. We're seeing it in the Arctic with the ice not lasting as long, and so therefore polar bears are suffering.

Grizzly bears are moving further north and maybe going to be competing with polar bears. Red foxes are moving north and probably going to be competing with arctic foxes. And so that's a big part of what's going on right now in anticipating and trying to deal with the issue of climate change when it comes to wildlife management.

FLATOW: Paul Yeager, let's talk a bit about snow, ice and the difference between different kinds of frozen water. Frost. How does frost form? Why do we get frost versus some - just ice particles? Or is it just ice forming on stuff?

YEAGER: Well, you know, frost is not really a precipitation type. You know, frost is when the air cools to the point that the water inside of the air condenses, and it's cold enough on the blades of grass or, you know, the ground to actually freeze. It's something that occurs right at the ground level. And it usually happens on a clear night when the sky is clear and all of the heat from the day is escaping and the atmosphere gets nice and chilly and allows that condensation process to occur close to the earth.

FLATOW: Is it sort of like frozen dew?

YEAGER: It is frozen dew, yeah.

FLATOW: Frozen.

YEAGER: Exactly.

FLATOW: Yeah. And is it true that there are no two snowflakes the same?

YEAGER: You know, that's an interesting debate. And, you know, I would find it very hard to believe that, given a number of snowflakes that have fallen over the, you know, hundreds of millions of years of the life of the planet, there haven't been two that have been the same. You know, just in - you know, I've seen estimates that on a given winter, it's estimated - or a given year, calendar year, winter for both hemispheres, that there are one with 24 zeroes after it number of snowflakes that fall each year.

And if you think about that many snowflakes kind of going through the same process to form, doing that year after year after year after year, you quickly get to the point where it's hard to believe that no two have been alike.

FLATOW: Mm-hmm. Andrew, let's talk a little bit about what celestial events we might look for and take advantage of the winter season.

FRAKNOI: Well, this is a great time for planets, Ira. If you go out right after sunset, Venus is in the west, and it's just super bright. So it will sort of knock you socks off astronomically. And if you go out January 26th, about an hour after sunset - put this on your social calendar.

FLATOW: I'm writing. I'm writing.

FRAKNOI: Take someone with you with whom you'd like to sit in the dark. But January 26th, the crescent moon will be right above Venus about an hour after sunset. It'll be gorgeous. Then Jupiter is high in the sky if you look south when the night falls, and it's visible in the evening sky, also quite bright and easy to spot. And then Saturn rises in the east just before 1 a.m., and is halfway up the sky by dawn. So Saturn is a beautiful morning object. If you have a small telescope or binoculars, you can see the rings of Saturn. You can see four of the bright moons around Jupiter. So there are lots of opportunities for planet-gazing, as well as stargazing. But I wanted to go back because if I may, Ira, we haven't answered the original question. We haven't said why there's winter. I thought...

FLATOW: Let me just - before we do that, let me remind everybody who we are. This is SCIENCE FRIDAY, from NPR. And I'm Ira Flatow, talking with Andrew Fraknoi. Go ahead. Why there is winter.

FRAKNOI: And I'm sorry, but I wanted to get this thing there before we have to go. That - the reason that the Earth's axis is tilted is the real reason for the seasons. And we think that early on, there was a collision, maybe one, maybe more of smaller forming planets with the Earth, which knocked us over. And so our planet has this tilted axis and has all the phenomena that we've been talking about. But not every planet had an accident like this. Venus orbits with its head held straight up. It has no seasons. Jupiter orbits with its head held straight up, and it has no seasons. So although we love the seasons and we kind of accept it as part of life on Earth, it's not a cosmic requirement. Now, I'm sure we'll find many planets out there among other stars that have no sense of winter or summer or anything like seasons.

FLATOW: 1-800-989-8255. We've just got a couple of minutes left. Paul, do you have any other comments you'd like to contribute about what makes winter special?

YEAGER: I think a lot of things make winter special, some of the things that we talked about. But, you know, personally, I love the snow. I think the snow is something that we can really learn to enjoy if we allow ourselves. We all had that innate love of the snow when we were young, and we would run around and play in the snow. But as we get older and a little bit more practical, we tend to stay more on the sidewalk than we do, you know, heading for the deepest snowdrift. And from that standpoint, I think that we could all learn to appreciate and love the weather because you're not going to change it. You might as well learn how to love it.

FLATOW: And, David Mizejewski, what are some of your favorite signs of winter, things that we can look for in nature?

MIZEJEWSKI: Well, as I said earlier, I think one of the best things about winter is the fact that you can go out and you can see a lot more than you can in other seasons simply because, at least in the north, there's not as many leaves. So I think it's a great time to get the family together, turn off the TV, and just make that commitment to go outside, get that fresh air, get exercise and look for, say, last seasons birds' nests that are in the trees and the bushes that you didn't see before because they were hidden. Look for animal tracks if there's snow on the ground. Look up on the sky. That's a great time to watch for winter-resident birds - raptors, in particular. I love going hawk watching in the winter time because you can really spot, you know, the big red-tailed hawks and things like that.

So, you know, the other thing that I think is a - winter's a great time of year for is planning your garden. You know, for those folks that just can't take the cold and they really just don't want to deal with it, one way to do, you know, have a good time in the winter is to plan out your spring garden. And, of course, at National Wildlife Federation we want folks to plan their wildlife - their gardens with wildlife in mind. So planting native stuff that's going to look great, but also naturally feed the birds and the other critters. So that's a good time of year to do it, is really right now in January.

FLATOW: Yeah, and this is in - traditionally, this has been the month where the garden seed catalogs start flooding in.

MIZEJEWSKI: That's absolutely right, and there's a reason for it because, you know, people are - do get a little bit of cabin fever at this time of year, and they are dreaming of warmer of weather. So if you can't tolerate the cold and you don't want to get outside, you know, again, plan your springtime garden and, you know, bide it out - ride it out like some of the creatures that hibernate do.

FLATOW: I want to thank you all for taking time to be with us, and wish you all a very happy winter and a Happy New Year. Thanks for Andrew Fraknoi, professor of astronomy at Foothill College, Paul Yeager, author of the book "Weather Whys: Facts, Myths, and Oddities," and David Mizejewski. He is a naturalist with the National Wildlife Federation. Thanks again for joining us today.

MIZEJEWSKI: Thanks, Ira.

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