WEBVTT 00:00:07.599 --> 00:00:10.320 Howdy Star Gazers and welcome to this episode 00:00:10.320 --> 00:00:13.820 of Star Trails. My name is Drew and I'll be your 00:00:13.820 --> 00:00:16.359 guide to the night sky for the week of February 00:00:16.359 --> 00:00:20.620 the 1st through the 7th. This month we're turning 00:00:20.620 --> 00:00:23.219 our attention to the most familiar objects in 00:00:23.219 --> 00:00:27.239 the sky and asking why they still surprise us. 00:00:27.679 --> 00:00:30.839 Stars are the first objects we learn to recognize. 00:00:31.260 --> 00:00:35.119 They feel simple, steady, almost obvious, but 00:00:35.119 --> 00:00:38.549 they aren't. Over the next few episodes, we're 00:00:38.549 --> 00:00:41.469 going to stay with stars long enough for those 00:00:41.469 --> 00:00:44.829 assumptions to fall apart, and see what's left 00:00:44.829 --> 00:00:48.390 when we stop treating them as scenery. Later 00:00:48.390 --> 00:00:51.049 in this episode, we'll cover the night sky for 00:00:51.049 --> 00:00:53.750 this week, and we kick off the discussion of 00:00:53.750 --> 00:00:56.789 the first three chapters of Night Watch, a book 00:00:56.789 --> 00:00:59.770 that makes an excellent companion to this podcast. 00:01:00.200 --> 00:01:02.719 Whether you're tuning in from the backyard or 00:01:02.719 --> 00:01:05.439 the balcony, I'm glad you're here. So grab a 00:01:05.439 --> 00:01:08.040 comfortable spot under the night sky and let's 00:01:08.040 --> 00:01:13.159 get started. So I can almost hear the groans 00:01:13.159 --> 00:01:17.379 out there. Why stars and why multiple episodes 00:01:17.379 --> 00:01:21.099 dedicated to them? Some of you may even remember 00:01:21.099 --> 00:01:24.859 episode 48, which was all about stars. And in 00:01:24.859 --> 00:01:27.319 fact, it's one of the shows I recommend to new 00:01:27.319 --> 00:01:30.159 listeners. Our discussion tonight will cover 00:01:30.159 --> 00:01:33.420 some similar but different ground. We're going 00:01:33.420 --> 00:01:35.739 to challenge what you think you know about these 00:01:35.739 --> 00:01:38.739 building blocks of the universe, or at least 00:01:38.739 --> 00:01:41.299 reframe them in a way that encourages taking 00:01:41.299 --> 00:01:44.680 a fresh look at them. Today's show will cover 00:01:44.680 --> 00:01:48.739 what a star is and what it isn't, and over the 00:01:48.739 --> 00:01:51.459 next few weeks we'll dig deeper into the lives 00:01:51.459 --> 00:01:55.040 of stars, their connections to humanity, and 00:01:55.040 --> 00:01:58.709 their fantastic deaths. And finally, we'll break 00:01:58.709 --> 00:02:02.329 out data, statistics, and the random number generator 00:02:02.329 --> 00:02:05.590 to simulate the birth of half a million stars 00:02:05.590 --> 00:02:10.069 in our own little version of the Big Bang. Stars 00:02:10.069 --> 00:02:13.650 are anything but boring. We owe our existence 00:02:13.650 --> 00:02:17.050 to them. After all, and I'm quoting Carl Sagan 00:02:17.050 --> 00:02:21.729 here, we are made of star stuff. When we talk 00:02:21.729 --> 00:02:24.409 about stars, we usually start with a definition. 00:02:24.680 --> 00:02:28.860 A star is a ball of gas. A star is powered by 00:02:28.860 --> 00:02:32.500 nuclear fusion. A star shines because hydrogen 00:02:32.500 --> 00:02:36.259 is being turned into helium in its core. And 00:02:36.259 --> 00:02:39.939 all of that is true, but it's also an oversimplification. 00:02:40.620 --> 00:02:43.659 A star isn't an object in the way we normally 00:02:43.659 --> 00:02:48.460 mean that word. It's more like a process. A temporary 00:02:48.460 --> 00:02:52.250 state. A long negotiation between forces that 00:02:52.250 --> 00:02:56.210 would very much prefer a different outcome. At 00:02:56.210 --> 00:03:00.849 its heart, a star begins with failure. In a stellar 00:03:00.849 --> 00:03:04.629 nursery, gravity pulls matter inward relentlessly. 00:03:05.110 --> 00:03:09.169 Gas collapses, compresses, and heats. In most 00:03:09.169 --> 00:03:12.090 cases, that collapse never gets far enough to 00:03:12.090 --> 00:03:16.139 matter. Clouds fragment, disperse, or drift back 00:03:16.139 --> 00:03:18.840 into obscurity without ever becoming anything 00:03:18.840 --> 00:03:23.060 we'd recognize as a star. But sometimes, rarely, 00:03:23.400 --> 00:03:26.639 that collapse doesn't happen. Pressure rises, 00:03:27.020 --> 00:03:30.560 temperatures climb. Long before fusion ignites, 00:03:30.840 --> 00:03:34.979 a proto -star is born. Hot, dense, glowing, not 00:03:34.979 --> 00:03:37.979 because it's burning fuel, but because it's falling 00:03:37.979 --> 00:03:42.159 inward. That phase can last millions of years, 00:03:42.360 --> 00:03:45.819 with gravity doing nearly all the work. Only 00:03:45.819 --> 00:03:48.740 when the core reaches extreme temperatures does 00:03:48.740 --> 00:03:52.379 hydrogen fusion finally begin. At that moment, 00:03:52.520 --> 00:03:55.919 gravity is interrupted. Outward pressure pushes 00:03:55.919 --> 00:04:00.020 back. The collapse slows not because it's failed, 00:04:00.240 --> 00:04:03.759 but because it's been delayed. Fusion doesn't 00:04:03.759 --> 00:04:07.080 create a star so much as it delays the inevitable. 00:04:07.469 --> 00:04:11.110 A star is what happens when gravity is stopped 00:04:11.110 --> 00:04:15.930 temporarily. That balance is everything. If fusion 00:04:15.930 --> 00:04:20.069 weakens, gravity wins. If gravity is resisted 00:04:20.069 --> 00:04:23.829 too strongly, the star swells, sheds mass, or 00:04:23.829 --> 00:04:27.689 destabilizes. There's no permanent state here, 00:04:27.889 --> 00:04:31.769 only equilibrium held for a while. And that's 00:04:31.769 --> 00:04:35.750 what a star is. And it's important to say what 00:04:35.750 --> 00:04:41.470 a star is not. A star is not stable. We imagine 00:04:41.470 --> 00:04:45.370 stars as eternal, fixed points in the sky, but 00:04:45.370 --> 00:04:48.410 that stability is an illusion created by human 00:04:48.410 --> 00:04:52.129 lifetimes. Even the longest -lived stars are 00:04:52.129 --> 00:04:56.069 burning through finite fuel. Some burn recklessly 00:04:56.069 --> 00:05:00.689 fast. Others sip slowly, but none escape the 00:05:00.689 --> 00:05:04.189 clock. We often describe stellar life cycles 00:05:04.189 --> 00:05:08.189 as neat stages, and you've probably seen diagrams 00:05:08.189 --> 00:05:12.230 of this in books. Birth, main sequence, giant, 00:05:12.589 --> 00:05:16.449 and eventually remnant. It's as if stars politely 00:05:16.449 --> 00:05:20.430 queue up in advance and order. But nature doesn't 00:05:20.430 --> 00:05:25.050 respect our diagrams. Massive stars rotate violently. 00:05:25.569 --> 00:05:28.550 They lose material, they pulse, they interact 00:05:28.550 --> 00:05:33.079 with companions. Some skip stages some reverse 00:05:33.079 --> 00:05:36.540 course some collapse early many never follow 00:05:36.540 --> 00:05:41.040 the standard path at all The life cycle we teach 00:05:41.040 --> 00:05:45.180 is an average and most stars lives are messier 00:05:45.180 --> 00:05:49.220 and more complicated Here's a wild fact most 00:05:49.220 --> 00:05:54.019 stars are not alone Solitary stars like our Sun 00:05:54.019 --> 00:05:57.610 are kind of unusual The majority of stars form 00:05:57.610 --> 00:06:01.029 in pairs or groups, and their neighbors matter. 00:06:01.990 --> 00:06:05.410 Companions exchange mass, distort orbits, and 00:06:05.410 --> 00:06:08.910 alter fates. Some of the most dramatic, stellar 00:06:08.910 --> 00:06:12.290 events we know about, certain supernova among 00:06:12.290 --> 00:06:15.670 them, simply cannot happen unless a second star 00:06:15.670 --> 00:06:19.750 is involved. A star's destiny is often shaped 00:06:19.750 --> 00:06:23.149 not just by what it is, but by who it lives with. 00:06:23.360 --> 00:06:27.379 Stars are social objects, yet we often regard 00:06:27.379 --> 00:06:32.379 them as solitary. When a star does reach a relatively 00:06:32.379 --> 00:06:35.879 stable phase, what we call the main sequence, 00:06:36.199 --> 00:06:40.279 it sounds calm, ordinary, normal, but it isn't. 00:06:40.560 --> 00:06:43.560 A star's life is that of contained violence, 00:06:44.259 --> 00:06:47.459 internal turmoil, energy constantly trying to 00:06:47.459 --> 00:06:51.879 shatter the grip of gravity. Inside a main sequence 00:06:51.879 --> 00:06:55.800 star, hydrogen nuclei are constantly fusing into 00:06:55.800 --> 00:06:59.399 helium under crushing pressure. Enormous amounts 00:06:59.399 --> 00:07:02.519 of mass are converted directly into energy every 00:07:02.519 --> 00:07:06.740 second. Gravity pushes inward. Fusion pushes 00:07:06.740 --> 00:07:10.720 outward. What we experience as starlight begins 00:07:10.720 --> 00:07:14.240 deep in the core, but it doesn't escape easily. 00:07:15.019 --> 00:07:18.060 A photon created there doesn't travel straight 00:07:18.060 --> 00:07:21.779 to the surface. It ricochets. It's absorbed and 00:07:21.779 --> 00:07:24.560 re -emitted, bounced and scattered again and 00:07:24.560 --> 00:07:27.540 again. That journey can take tens of thousands, 00:07:27.819 --> 00:07:31.259 even millions of years. By the time that light 00:07:31.259 --> 00:07:34.319 finally escapes into space, the conditions that 00:07:34.319 --> 00:07:39.579 created it may no longer even exist. So a star's 00:07:39.579 --> 00:07:43.829 glow is actually a slow leak. albeit the mechanism 00:07:43.829 --> 00:07:47.509 that allows us to see them. Now let's talk about 00:07:47.509 --> 00:07:51.550 color. We say stars are blue, white, yellow, 00:07:51.850 --> 00:07:55.230 orange, or red as if color were a decoration. 00:07:55.889 --> 00:08:00.250 But color is a diagnosis. A star's color tells 00:08:00.250 --> 00:08:03.949 us its surface temperature. Blue stars burn hotter 00:08:03.949 --> 00:08:08.029 and faster. Red stars burn cooler and often far 00:08:08.029 --> 00:08:11.759 longer. or they are swollen giants nearing the 00:08:11.759 --> 00:08:15.720 end of their balance. Human eyes are terrible 00:08:15.720 --> 00:08:19.220 tools for measuring stellar color. In low light, 00:08:19.420 --> 00:08:22.839 our color vision collapses. The atmosphere bends 00:08:22.839 --> 00:08:26.860 and splits starlight. Near the horizon, stars 00:08:26.860 --> 00:08:30.800 shimmer into rainbows. Sirius flashes blue, red, 00:08:30.920 --> 00:08:34.000 and green, not because it's changing, but because 00:08:34.000 --> 00:08:38.009 Earth won't hold still. Astrophotography has 00:08:38.009 --> 00:08:40.490 trained us to expect color, but much of what 00:08:40.490 --> 00:08:44.090 we see is interpretation layered atop reality, 00:08:44.509 --> 00:08:47.690 calibration, enhancement, and long exposure, 00:08:48.330 --> 00:08:51.110 revealing truths our eyes were never built to 00:08:51.110 --> 00:08:54.769 perceive directly. The sky isn't lying, but it 00:08:54.769 --> 00:08:58.610 isn't being entirely honest either. The same 00:08:58.610 --> 00:09:02.110 is true for brightness. When we say a star is 00:09:02.110 --> 00:09:04.490 bright, we're not describing the star itself. 00:09:04.870 --> 00:09:08.509 We're describing a measurement. Astronomers use 00:09:08.509 --> 00:09:12.450 a system called magnitude, a backward scale where 00:09:12.450 --> 00:09:15.889 smaller numbers mean brighter objects and negative 00:09:15.889 --> 00:09:19.210 numbers mark the brightest of all. It's an older 00:09:19.210 --> 00:09:22.509 system refined mathematically but still rooted 00:09:22.509 --> 00:09:26.950 in human perception. You'll often see stars categorized 00:09:26.950 --> 00:09:30.289 by magnitude. Historically, ancient astronomers 00:09:30.289 --> 00:09:33.850 catalogued stars down to about the sixth magnitude, 00:09:34.250 --> 00:09:37.169 because that's where stars stop being reliably 00:09:37.169 --> 00:09:41.169 visible to most people under natural skies. That's 00:09:41.169 --> 00:09:44.049 why the original magnitude system ended there. 00:09:44.190 --> 00:09:47.070 It was literally the edge of human perception. 00:09:47.750 --> 00:09:50.570 In light -polluted skies, we might be able to 00:09:50.570 --> 00:09:54.659 only see stars around magnitude 3. Binoculars 00:09:54.659 --> 00:09:57.279 can draw in more light, often allowing us to 00:09:57.279 --> 00:10:02.460 see stars at plus 9 or plus 10. Magnitude doesn't 00:10:02.460 --> 00:10:05.899 tell us how powerful a star is, it tells us how 00:10:05.899 --> 00:10:10.100 bright it appears from here on Earth. Brightness 00:10:10.100 --> 00:10:13.159 is a collaboration between energy output and 00:10:13.159 --> 00:10:16.620 distance, and we only experience the final result. 00:10:17.960 --> 00:10:21.100 This is where our intuition really breaks down. 00:10:21.519 --> 00:10:24.960 The stars that dominate our night sky, the ones 00:10:24.960 --> 00:10:28.220 we learn first, the ones with names, are not 00:10:28.220 --> 00:10:32.320 typical stars. They're either unusually luminous, 00:10:32.759 --> 00:10:37.620 unusually close, or both. They're giants, supergiants, 00:10:37.799 --> 00:10:41.139 or nearby standouts. These account for about 00:10:41.139 --> 00:10:45.360 99 % of the stars we see from Earth. The vast 00:10:45.360 --> 00:10:48.039 majority of stars in the Milky Way are nothing 00:10:48.039 --> 00:10:51.919 like them. Most stars in our galaxy are small, 00:10:52.240 --> 00:10:56.460 cool, dim, red dwarves. They burn slowly. They 00:10:56.460 --> 00:10:59.899 live for trillions of years. And from Earth, 00:11:00.179 --> 00:11:02.620 almost all of them are completely invisible. 00:11:03.440 --> 00:11:06.019 They don't announce themselves, they don't dominate 00:11:06.019 --> 00:11:08.799 constellations, and they don't shape mythology. 00:11:09.659 --> 00:11:11.820 If you could somehow turn down the brightness 00:11:11.820 --> 00:11:15.580 bias of the sky, if you could see all stars equally, 00:11:15.820 --> 00:11:18.559 regardless of distance, The familiar patterns 00:11:18.559 --> 00:11:21.960 we know would dissolve. The night would be flooded 00:11:21.960 --> 00:11:26.679 with faint, unassuming points of light. Not every 00:11:26.679 --> 00:11:30.299 collapsing object even becomes a star as we know 00:11:30.299 --> 00:11:33.799 them. Sometimes a cloud gathers enough mass to 00:11:33.799 --> 00:11:36.679 heat up and glow faintly, but never enough to 00:11:36.679 --> 00:11:40.340 sustain hydrogen fusion. These objects are called 00:11:40.340 --> 00:11:43.919 brown dwarves. They're too massive to be planets 00:11:43.919 --> 00:11:48.159 and too small to be stars. Some briefly fuse 00:11:48.159 --> 00:11:51.600 a heavy form of hydrogen called deuterium, buying 00:11:51.600 --> 00:11:54.980 them a short -lived glow. Then gravity resumes 00:11:54.980 --> 00:11:58.820 its work, and they cool and fade. Brown dwarfs 00:11:58.820 --> 00:12:02.179 are not stars that died. They are stars that 00:12:02.179 --> 00:12:05.679 never quite lived. You'll sometimes hear Jupiter 00:12:05.679 --> 00:12:09.779 called a failed star. It isn't, because Jupiter 00:12:09.779 --> 00:12:13.960 never tried to ignite. Planets form differently, 00:12:14.220 --> 00:12:16.879 assembling piece by piece in a disk around a 00:12:16.879 --> 00:12:19.899 young star. Jupiter would need to be more than 00:12:19.899 --> 00:12:23.480 70 times more massive to even approach fusion. 00:12:24.799 --> 00:12:28.159 Brown dwarves remind us that star formation is 00:12:28.159 --> 00:12:31.860 not guaranteed. The universe produces many more 00:12:31.860 --> 00:12:36.320 almosts than successes. Here's another strange 00:12:36.320 --> 00:12:40.039 fact. We can't actually observe stars directly. 00:12:40.460 --> 00:12:44.259 Every star in the night sky, except one, is an 00:12:44.259 --> 00:12:48.179 unresolved point of light, with no surface detail, 00:12:48.500 --> 00:12:52.539 no texture, just photons collected and interpreted. 00:12:53.460 --> 00:12:56.580 Our sun is the only star we can truly study. 00:12:57.179 --> 00:13:00.480 We observe it from Earth and from space. We send 00:13:00.480 --> 00:13:03.820 probes into its atmosphere. We watch its surface 00:13:03.820 --> 00:13:08.019 churn, flare, ripple, and erupt. Then we take 00:13:08.019 --> 00:13:11.399 what we learn from the sun and extend it, carefully, 00:13:11.600 --> 00:13:15.240 to every other star in the universe. Stars are 00:13:15.240 --> 00:13:18.419 not understood individually. They are understood 00:13:18.419 --> 00:13:22.059 statistically. The sun is our Rosetta Stone. 00:13:23.720 --> 00:13:27.639 Stars don't exist just to shine. They exist to 00:13:27.639 --> 00:13:32.120 transform matter. Inside stars, simple elements 00:13:32.120 --> 00:13:35.720 are rearranged into more complex ones. And when 00:13:35.720 --> 00:13:39.240 stars die, sometimes gently, sometimes violently, 00:13:39.799 --> 00:13:42.759 they return that processed material to the galaxy. 00:13:43.639 --> 00:13:47.179 Every atom heavier than hydrogen and helium owes 00:13:47.179 --> 00:13:50.580 its existence to stars that lived and failed 00:13:50.580 --> 00:13:54.360 long before the sun was born. Stars are not the 00:13:54.360 --> 00:13:57.799 universe's final products. They're its workshops. 00:13:59.179 --> 00:14:01.899 And that leads to the most important thing a 00:14:01.899 --> 00:14:05.879 star is not. A star is not the main character 00:14:05.879 --> 00:14:09.419 of the universe. We build our stories around 00:14:09.419 --> 00:14:12.399 stars because we orbit one, because they light 00:14:12.399 --> 00:14:15.200 our nights, because they're visually generous. 00:14:15.860 --> 00:14:18.960 But stars are temporary fixtures in a universe 00:14:18.960 --> 00:14:23.000 that prefers darkness, cold, and emptiness. They 00:14:23.000 --> 00:14:26.860 are brief leaks of energy in a cosmos otherwise 00:14:26.860 --> 00:14:29.840 content to coast. And that doesn't make them 00:14:29.840 --> 00:14:33.730 insignificant. It makes them extraordinary. And, 00:14:33.889 --> 00:14:36.490 we happen to live during one of those pauses, 00:14:36.990 --> 00:14:40.629 on a planet warmed by a single star surrounded 00:14:40.629 --> 00:14:43.830 by thousands more, most of which we'll never 00:14:43.830 --> 00:15:05.379 see, all of which will eventually fail. After 00:15:05.379 --> 00:15:08.019 a quick break we'll return with this week's Night 00:15:08.019 --> 00:15:10.580 Sky report and I'll share my thoughts on the 00:15:10.580 --> 00:15:13.480 first three chapters of Night Watch. Stay with 00:15:13.480 --> 00:15:29.179 us. Welcome back. I don't know about you, but 00:15:29.179 --> 00:15:31.980 the weather here in my area has been pretty rough 00:15:31.980 --> 00:15:35.419 for the past week, owing to winter storms, low 00:15:35.419 --> 00:15:39.360 temperatures, ice, and snow. I think I managed 00:15:39.360 --> 00:15:42.799 to see the moon and some stars just one evening 00:15:42.799 --> 00:15:45.980 in the past week. I know a lot of folks are being 00:15:45.980 --> 00:15:48.879 impacted by winter weather right now, and many 00:15:48.879 --> 00:15:51.820 of you are iced in like Superman in the Fortress 00:15:51.820 --> 00:15:55.259 of Solitude. So hopefully wherever you are, you're 00:15:55.259 --> 00:15:58.580 at least staying warm. As we look at the sky 00:15:58.580 --> 00:16:00.779 tonight through the seventh, one of the first 00:16:00.779 --> 00:16:03.559 things you'll notice is the full moon, the snow 00:16:03.559 --> 00:16:06.960 moon, shining high and bright early in the week. 00:16:07.399 --> 00:16:10.980 The full phase occurs tonight. In much of the 00:16:10.980 --> 00:16:14.080 Northern Hemisphere, February is among the snowiest 00:16:14.080 --> 00:16:17.100 months of the year, so cultures from Native American 00:16:17.100 --> 00:16:21.120 tribes to colonial settlers use this snow moon 00:16:21.120 --> 00:16:24.519 as kind of a natural calendar marker. It's also 00:16:24.519 --> 00:16:27.690 been called the hungry moon, the Bear Moon, the 00:16:27.690 --> 00:16:31.009 Ice Moon, and other names rooted in the seasons 00:16:31.009 --> 00:16:34.649 and the challenges winter brings. This full moon 00:16:34.649 --> 00:16:38.090 means faint deep sky objects will be washed out 00:16:38.090 --> 00:16:40.950 early in the week. That said, bright targets 00:16:40.950 --> 00:16:44.710 like open clusters and contrasty stellar fields 00:16:44.710 --> 00:16:47.950 still hold up beautifully, and the moon's presence 00:16:47.950 --> 00:16:51.240 itself becomes part of the story. An interesting 00:16:51.240 --> 00:16:53.639 moment coming right at the start of the observation 00:16:53.639 --> 00:16:56.740 window is the moon's close association with the 00:16:56.740 --> 00:17:01.019 bright star Regulus in Leo. Tonight and into 00:17:01.019 --> 00:17:04.500 the second, the moon sits near Regulus, so close 00:17:04.500 --> 00:17:07.400 that from some parts of North America, it will 00:17:07.400 --> 00:17:11.039 even occult Regulus on the second. Be sure to 00:17:11.039 --> 00:17:13.740 check in with an app like Stellarium to determine 00:17:13.740 --> 00:17:17.039 the exact time of the occultation. For instance, 00:17:17.200 --> 00:17:20.400 at my location, the right limb of the moon will 00:17:20.400 --> 00:17:23.920 just barely graze Regulus around 9pm on that 00:17:23.920 --> 00:17:27.299 date. As the week progresses, the moon wanes 00:17:27.299 --> 00:17:30.559 to gibbous, which means later nights after moonset 00:17:30.559 --> 00:17:34.059 give cleaner views of star clusters and the subtler 00:17:34.059 --> 00:17:37.619 features in the winter sky. Planets this week 00:17:37.619 --> 00:17:40.400 are not the main attraction, but there are a 00:17:40.400 --> 00:17:43.559 couple worth noting. Jupiter is still visible 00:17:43.559 --> 00:17:46.200 in the early evening, shining brightly before 00:17:46.200 --> 00:17:49.700 it sinks toward the west. It's past its best 00:17:49.700 --> 00:17:52.500 opposition views, but it's still unmistakable 00:17:52.500 --> 00:17:55.920 and makes a good anchor point in the sky. Saturn 00:17:55.920 --> 00:17:58.920 is much fainter and lower and really requires 00:17:58.920 --> 00:18:02.019 binoculars or a telescope to appreciate, but 00:18:02.019 --> 00:18:05.680 it's there for patient observers. Now let's talk 00:18:05.680 --> 00:18:08.960 about stars and clusters, especially the ones 00:18:08.960 --> 00:18:12.450 people tend to overlook. High in the sky this 00:18:12.450 --> 00:18:15.549 week, you'll find the faint constellation Cancer. 00:18:16.529 --> 00:18:18.670 Cancer doesn't have any bright stars to announce 00:18:18.670 --> 00:18:21.950 itself, but it hides two excellent clusters that 00:18:21.950 --> 00:18:26.289 reward a slower look. The first is the Beehive 00:18:26.289 --> 00:18:30.390 cluster, also known as Messier 44. To the naked 00:18:30.390 --> 00:18:33.109 eye under darker skies, it appears as a soft 00:18:33.109 --> 00:18:36.750 patch of light. In binoculars, it explodes into 00:18:36.750 --> 00:18:39.750 dozens of stars scattered across a wide field. 00:18:40.059 --> 00:18:42.619 This is one of those objects that feels more 00:18:42.619 --> 00:18:46.019 natural in binoculars than in a telescope, and 00:18:46.019 --> 00:18:49.000 it's especially satisfying once the moon has 00:18:49.000 --> 00:18:53.359 dipped lower in the sky. Nearby is Messier 67, 00:18:53.759 --> 00:18:58.359 a very different kind of cluster. M67 is older, 00:18:58.759 --> 00:19:02.039 tighter, and more subdued. It doesn't jump out 00:19:02.039 --> 00:19:04.920 at you, but once you settle in, it feels dense 00:19:04.920 --> 00:19:08.180 and deliberate. almost like a fossil record of 00:19:08.180 --> 00:19:11.660 an earlier generation of stars. It's an excellent 00:19:11.660 --> 00:19:14.619 contrast to the beehive, and a reminder that 00:19:14.619 --> 00:19:18.059 not all clusters tell the same story. If you're 00:19:18.059 --> 00:19:20.640 willing to move your gaze a little farther south, 00:19:20.759 --> 00:19:24.619 look toward Monoceros, the unicorn. This is one 00:19:24.619 --> 00:19:27.599 of the most underappreciated winter constellations, 00:19:27.740 --> 00:19:30.059 largely because it's faint and doesn't resemble 00:19:30.059 --> 00:19:33.640 much of anything at a first glance. But Monoceros 00:19:33.640 --> 00:19:37.210 is rich in star clusters. One standout here is 00:19:37.210 --> 00:19:42.190 NGC 2244, the central cluster of the Rosette 00:19:42.190 --> 00:19:45.930 region. Even if the surrounding nebula is washed 00:19:45.930 --> 00:19:48.869 out by moonlight, the cluster itself is visible 00:19:48.869 --> 00:19:52.250 in binoculars or a small scope as a loose grouping 00:19:52.250 --> 00:19:56.049 of young stars. This is a great object to revisit 00:19:56.049 --> 00:19:58.849 later in the month under darker skies, but it's 00:19:58.849 --> 00:20:03.309 still worth finding now. Back in Orion, but away 00:20:03.309 --> 00:20:06.069 from the famous nebula, there's a small charming 00:20:06.069 --> 00:20:11.309 cluster called NGC 2169. Through binoculars or 00:20:11.309 --> 00:20:14.609 a low -power telescope, its stars form a pattern 00:20:14.609 --> 00:20:18.369 that looks like the number 37. It's subtle and 00:20:18.369 --> 00:20:21.250 a little whimsical. This is also a good week 00:20:21.250 --> 00:20:24.650 to simply wander star fields, spend some time 00:20:24.650 --> 00:20:28.569 around Procyon and Canis Minor, or scan the regions 00:20:28.569 --> 00:20:32.579 between Orion and Gemini. These areas don't have 00:20:32.579 --> 00:20:35.680 marquee objects, but they're full of subtle patterns, 00:20:36.140 --> 00:20:39.319 faint companions, and gentle color contrasts 00:20:39.319 --> 00:20:41.420 that are easy to miss when you're always chasing 00:20:41.420 --> 00:20:44.920 famous targets. Because the moon is bright early 00:20:44.920 --> 00:20:47.539 in the week, think about timing rather than fighting 00:20:47.539 --> 00:20:51.619 conditions. Step outside before moonrise or stay 00:20:51.619 --> 00:20:55.359 out after it sets. Use binoculars, let your eyes 00:20:55.359 --> 00:21:05.839 adapt, and don't rush. It's finally time to discuss 00:21:05.839 --> 00:21:09.680 our first book club selection, Night Watch, by 00:21:09.680 --> 00:21:12.759 Terence Dickinson. I chose this book because 00:21:12.759 --> 00:21:15.299 it's often recommended as a good starting point 00:21:15.299 --> 00:21:18.839 for beginner stargazers. That doesn't mean seasoned 00:21:18.839 --> 00:21:22.200 observers can't enjoy it. Every time I open it, 00:21:22.259 --> 00:21:24.680 I learn something new, and I've mentioned it 00:21:24.680 --> 00:21:27.000 before, but this book could be an accompanying 00:21:27.000 --> 00:21:29.759 text for this podcast because it's really aimed 00:21:29.759 --> 00:21:33.849 at backyard binocular observers. Before we go 00:21:33.849 --> 00:21:36.750 any further, it's worth talking briefly about 00:21:36.750 --> 00:21:39.609 editions, because Nightwatch has been updated 00:21:39.609 --> 00:21:43.009 several times over the years, and you may not 00:21:43.009 --> 00:21:47.029 all be reading the same one. I'm personally working 00:21:47.029 --> 00:21:49.930 from the 4th edition, which technically only 00:21:49.930 --> 00:21:54.410 carries star charts through 2025. That's still 00:21:54.410 --> 00:21:57.369 completely fine for what we're doing here. The 00:21:57.369 --> 00:21:59.890 fundamentals haven't changed, the sky hasn't 00:21:59.890 --> 00:22:02.750 rearranged itself, and everything in these early 00:22:02.750 --> 00:22:06.789 chapters remains solid and relevant. There is 00:22:06.789 --> 00:22:09.269 a new fifth edition, and if you're using that 00:22:09.269 --> 00:22:11.849 one, you'll notice a few meaningful upgrades. 00:22:12.410 --> 00:22:14.930 The photography throughout the book is more modern, 00:22:15.130 --> 00:22:18.269 with newer astrophotography replacing some of 00:22:18.269 --> 00:22:21.230 the older images, many of which, in earlier editions, 00:22:21.630 --> 00:22:24.509 were taken by Dickinson himself, and definitely 00:22:24.509 --> 00:22:27.990 show their age. The fifth edition also expands 00:22:27.990 --> 00:22:30.930 coverage of the southern sky, which is valuable 00:22:30.930 --> 00:22:33.509 in general, even if we don't spend much time 00:22:33.509 --> 00:22:36.630 there on this podcast. There's also more material 00:22:36.630 --> 00:22:39.849 related to modern observing and imaging techniques, 00:22:40.390 --> 00:22:44.109 including astrophotography. That said, for our 00:22:44.109 --> 00:22:47.289 purposes, especially these opening chapters focused 00:22:47.289 --> 00:22:50.589 on orientation, scale, and backyard observing, 00:22:51.089 --> 00:22:53.730 the fourth and fifth editions are philosophically 00:22:53.730 --> 00:22:57.559 identical. The words still land the same, the 00:22:57.559 --> 00:23:00.559 guidance still works, and the sky they describe 00:23:00.559 --> 00:23:03.779 is the same one above your head tonight. So if 00:23:03.779 --> 00:23:06.079 you've got the fifth edition, great. If you're 00:23:06.079 --> 00:23:08.440 working from the fourth, don't worry, you're 00:23:08.440 --> 00:23:11.039 not behind and you're not missing anything essential 00:23:11.039 --> 00:23:15.039 for this discussion. This opening chapter, Discovering 00:23:15.039 --> 00:23:17.900 the Cosmos, is brief, but it's doing something 00:23:17.900 --> 00:23:21.259 important. Dickinson makes it very clear that 00:23:21.259 --> 00:23:24.180 astronomy doesn't begin with equations or equipment. 00:23:24.380 --> 00:23:27.859 It begins with attention. He frames astronomy 00:23:27.859 --> 00:23:30.240 as something you can do with your eyes alone, 00:23:30.460 --> 00:23:33.359 then gradually expands that to binoculars and 00:23:33.359 --> 00:23:36.160 telescopes without ever making the naked eye 00:23:36.160 --> 00:23:39.579 feel like a lesser option. One line of thinking 00:23:39.579 --> 00:23:42.500 that really resonated with me is his idea that 00:23:42.500 --> 00:23:46.220 we're all celestial tourists, and just like traveling 00:23:46.220 --> 00:23:49.220 somewhere new on Earth, the experience gets richer 00:23:49.220 --> 00:23:51.460 when you understand a little about where you 00:23:51.460 --> 00:23:54.519 are and what you're looking at. You don't need 00:23:54.519 --> 00:23:57.180 to be an expert, but knowing the lay of the land 00:23:57.180 --> 00:24:00.619 changes everything. That philosophy should feel 00:24:00.619 --> 00:24:04.119 very familiar to listeners of this podcast. The 00:24:04.119 --> 00:24:07.279 goal isn't to pile on jargon or technical baggage. 00:24:07.680 --> 00:24:11.180 It's to untangle it just enough so the sky starts 00:24:11.180 --> 00:24:15.660 feeling accessible. If Chapter 1 is an invitation, 00:24:16.299 --> 00:24:20.380 Chapter 2 is perspective therapy. This chapter, 00:24:20.559 --> 00:24:24.450 The Universe in Eleven Steps, walks outward from 00:24:24.450 --> 00:24:27.410 Earth in steps, each one expanding the scale 00:24:27.410 --> 00:24:30.390 by factors of a hundred, until you're suddenly 00:24:30.390 --> 00:24:33.450 dealing with distances and sizes that stop making 00:24:33.450 --> 00:24:37.730 intuitive sense. And that's the point. Dickinson 00:24:37.730 --> 00:24:40.670 is taking an honest look at the problem of scale 00:24:40.670 --> 00:24:43.809 in our universe and how to begin to comprehend 00:24:43.809 --> 00:24:47.220 its vastness. What really stands out here is 00:24:47.220 --> 00:24:50.359 how visual this chapter is. Even if you're familiar 00:24:50.359 --> 00:24:52.799 with the structure of the solar system, the Milky 00:24:52.799 --> 00:24:56.240 Way, and beyond, seeing it laid out this way 00:24:56.240 --> 00:24:59.220 reminds you just how strange our situation is. 00:24:59.880 --> 00:25:02.819 We're not at the center of anything. We're not 00:25:02.819 --> 00:25:06.259 special in location. We're riding along in a 00:25:06.259 --> 00:25:10.269 galaxy that's one among billions. By the time 00:25:10.269 --> 00:25:12.809 this chapter ends, you have a much better sense 00:25:12.809 --> 00:25:15.970 of where the night sky fits into the larger universe. 00:25:16.869 --> 00:25:19.250 Now, this is where Night Watch really starts 00:25:19.250 --> 00:25:23.069 to feel like a companion to this podcast. Chapter 00:25:23.069 --> 00:25:27.130 3, Backyard Astronomy, is densely packed, but 00:25:27.130 --> 00:25:30.490 it's written with a light touch. It covers how 00:25:30.490 --> 00:25:34.349 the sky moves, while stars appear to rotate around 00:25:34.349 --> 00:25:38.319 Polaris. and how Earth's rotation creates that 00:25:38.319 --> 00:25:41.779 slow celestial swirl we talked about earlier 00:25:41.779 --> 00:25:45.039 this year on the show. One of my favorite sections 00:25:45.039 --> 00:25:48.059 is Dickinson's discussion of measuring the sky 00:25:48.059 --> 00:25:52.759 using your hands, how a fist held at arm's length 00:25:52.759 --> 00:25:56.259 spans about 10 degrees, and how your fingers 00:25:56.259 --> 00:25:59.579 can become a built -in ruler. This is such a 00:25:59.579 --> 00:26:02.400 simple idea, but it's incredibly empowering once 00:26:02.400 --> 00:26:06.200 you start using it. Suddenly, the sky feels measurable, 00:26:06.799 --> 00:26:10.299 navigable, and less abstract. He also does a 00:26:10.299 --> 00:26:13.019 nice job showing how familiar constellations 00:26:13.019 --> 00:26:16.819 act as signposts. Using the Big Dipper to find 00:26:16.819 --> 00:26:21.140 stars like Arcturus, Vega, Deneb, and Regulus 00:26:21.140 --> 00:26:24.279 turns the sky into a map instead of a guessing 00:26:24.279 --> 00:26:28.210 game. There's also a subtle but important discussion 00:26:28.210 --> 00:26:31.130 of star brightness that ties directly into something 00:26:31.130 --> 00:26:34.549 we talked about earlier in this episode. Most 00:26:34.549 --> 00:26:37.349 of the stars we can see from Earth are not typical 00:26:37.349 --> 00:26:40.509 stars. They're larger and more luminous than 00:26:40.509 --> 00:26:44.809 our Sun, and yet the Sun itself is brighter and 00:26:44.809 --> 00:26:48.329 larger than more than 90 % of the stars in the 00:26:48.329 --> 00:26:52.470 Milky Way. This chapter also introduces constellations, 00:26:52.650 --> 00:26:55.130 explains why they're named the way they are, 00:26:55.130 --> 00:26:58.710 and even includes a pronunciation guide, and 00:26:58.710 --> 00:27:01.569 I'll admit, that was humbling. There are a few 00:27:01.569 --> 00:27:04.670 names in here that I've been confidently mispronouncing 00:27:04.670 --> 00:27:08.569 for years. Finally, Dickinson touches on the 00:27:08.569 --> 00:27:11.690 stuff that moves, such as satellites, rocket 00:27:11.690 --> 00:27:15.049 bodies, and space stations, and reminds us that 00:27:15.049 --> 00:27:17.930 not everything crossing the sky is ancient or 00:27:17.930 --> 00:27:21.970 distant. Some of it is very much ours. What I 00:27:21.970 --> 00:27:24.190 appreciate most about these opening chapters 00:27:24.190 --> 00:27:26.730 is they don't assume you're starting from zero, 00:27:26.789 --> 00:27:29.730 but they're easy to understand even if you are. 00:27:30.569 --> 00:27:32.750 I also want to take a moment to say something 00:27:32.750 --> 00:27:36.549 in defense of books themselves. Like many of 00:27:36.549 --> 00:27:39.490 you, I tend to read books on a device these days, 00:27:39.710 --> 00:27:43.150 like a Kindle. Nightwatch is not available as 00:27:43.150 --> 00:27:47.410 a download, and that's not a bad thing. Astronomy 00:27:47.410 --> 00:27:50.509 is a field that moves quickly in some ways and 00:27:50.509 --> 00:27:53.990 incredibly slow in others, and books like Night 00:27:53.990 --> 00:27:57.509 Watch sit right at that intersection. The technology 00:27:57.509 --> 00:28:00.630 changes, the photography improves, the charts 00:28:00.630 --> 00:28:03.950 get updated, but the sky doesn't reinvent itself 00:28:03.950 --> 00:28:07.750 every year. There's something uniquely valuable 00:28:07.750 --> 00:28:11.450 about a well -designed astronomy book. It invites 00:28:11.450 --> 00:28:15.430 you to slow down, flip a few pages, and let ideas 00:28:15.430 --> 00:28:18.890 settle. That's why Nightwatch feels like such 00:28:18.890 --> 00:28:22.190 a natural fit for this show. It's trying to teach 00:28:22.190 --> 00:28:25.529 you how to look, how to think, and how to stay 00:28:25.529 --> 00:28:29.269 curious. It's exactly the right tool for the 00:28:29.269 --> 00:28:32.410 kind of astronomy we're practicing here. We'll 00:28:32.410 --> 00:28:35.390 discuss the next two chapters two weeks from 00:28:35.390 --> 00:28:39.809 now. Chapter four is all about stars, which aligns 00:28:39.809 --> 00:28:43.109 nicely with this month's theme. Chapter five 00:28:43.109 --> 00:28:46.529 is a discussion about stargazing equipment. and 00:28:46.529 --> 00:28:49.289 includes an honest and eye -opening discussion 00:28:49.289 --> 00:28:52.309 about the nature of telescopes. I think you'll 00:28:52.309 --> 00:28:57.109 enjoy both sections. Also, the Nightwatch website, 00:28:57.410 --> 00:29:01.690 nightwatchbook .com, contains additional content 00:29:01.690 --> 00:29:04.650 such as videos and links to online resources 00:29:04.650 --> 00:29:07.930 that complement the book. Check that out if you 00:29:07.930 --> 00:29:10.829 get a chance. And I don't have any homework to 00:29:10.829 --> 00:29:13.029 give out or anything, but if you want to share 00:29:13.029 --> 00:29:15.279 your thoughts on the book, Feel free to send 00:29:15.279 --> 00:29:21.180 me a note via the show website. That's going 00:29:21.180 --> 00:29:23.920 to do it for this week. If you found this episode 00:29:23.920 --> 00:29:26.140 interesting, please share it with a friend who 00:29:26.140 --> 00:29:29.019 might enjoy it. The easiest way to do that is 00:29:29.019 --> 00:29:33.480 by sending folks to our website, StarTrails .Show. 00:29:34.079 --> 00:29:36.640 And if you want to support the show, use the 00:29:36.640 --> 00:29:39.460 link on the site to buy me a coffee. That really 00:29:39.460 --> 00:29:43.150 helps. Be sure to follow Star Trails on Blue 00:29:43.150 --> 00:29:46.549 Sky and YouTube. Links are in the show notes. 00:29:47.289 --> 00:29:49.950 Until we meet again beneath the stars, clear 00:29:49.950 --> 00:29:50.789 skies everyone.