WEBVTT 00:00:07.959 --> 00:00:10.300 Howdy stargazers, and welcome to this episode 00:00:10.300 --> 00:00:13.480 of Star Trails. My name is Drew, and I'll be 00:00:13.480 --> 00:00:16.339 your guide to the night sky for the week of February 00:00:16.339 --> 00:00:20.359 the 15th to the 21st. In this episode, we're 00:00:20.359 --> 00:00:23.160 continuing this month's star theme, but we're 00:00:23.160 --> 00:00:26.190 taking a bit of a nerdy detour. We're going to 00:00:26.190 --> 00:00:29.589 run some code that simulates a small galaxy containing 00:00:29.589 --> 00:00:33.070 a half million stars. Then we'll roll the clock 00:00:33.070 --> 00:00:36.429 forward to see what's left after 10 billion years. 00:00:37.250 --> 00:00:39.850 The results are intriguing and shed a little 00:00:39.850 --> 00:00:42.609 light on what our universe might look like billions 00:00:42.609 --> 00:00:46.189 or even trillions of years from now. We'll also 00:00:46.189 --> 00:00:49.250 set our sights on some of the most infamous stars 00:00:49.250 --> 00:00:52.729 in our galaxy, from the closest ones to the most 00:00:52.729 --> 00:00:55.689 deadly. Later in the show, we'll take a look 00:00:55.689 --> 00:00:58.689 at this week's sky and visit the next two chapters 00:00:58.689 --> 00:01:02.770 of Night Watch in our book club segment. This 00:01:02.770 --> 00:01:05.590 is a longer episode, so grab a comfortable spot 00:01:05.590 --> 00:01:10.209 under the night sky and let's get started. We're 00:01:10.209 --> 00:01:13.769 in the midst of our month of star -themed episodes, 00:01:13.950 --> 00:01:17.590 so I want to do a thought experiment. One that 00:01:17.590 --> 00:01:20.769 lets us zoom out far beyond any single star. 00:01:21.120 --> 00:01:23.879 Instead of talking about individual objects, 00:01:24.019 --> 00:01:27.319 I wanted to ask a broader question. If stars 00:01:27.319 --> 00:01:30.200 form and evolve the way we think they do, which 00:01:30.200 --> 00:01:33.340 ones actually survive long enough to still be 00:01:33.340 --> 00:01:36.099 shining today or even trillions of years from 00:01:36.099 --> 00:01:39.359 now? And what can we learn from the stars that 00:01:39.359 --> 00:01:45.040 have already died? To explore that, I wrote a 00:01:45.040 --> 00:01:49.400 small Monte Carlo simulation in Python. Nothing 00:01:49.400 --> 00:01:53.019 too exotic, just a deliberately simplified galaxy 00:01:53.019 --> 00:01:56.659 that follows a few well -established astrophysical 00:01:56.659 --> 00:02:00.540 rules, and then lets randomness do the rest. 00:02:01.719 --> 00:02:05.200 Here's how the experiment works. First, we let 00:02:05.200 --> 00:02:09.080 stars form continuously over a span of 10 billion 00:02:09.080 --> 00:02:13.060 years. That number wasn't chosen at random. It's 00:02:13.060 --> 00:02:16.370 roughly the age of the Milky Way. And it's also 00:02:16.370 --> 00:02:19.669 about how long a sun -like star spends on the 00:02:19.669 --> 00:02:22.969 main sequence. In other words, it's a reasonable 00:02:22.969 --> 00:02:26.050 stand -in for the lifetime of a mature spiral 00:02:26.050 --> 00:02:31.389 galaxy up to present day. In the code, that simply 00:02:31.389 --> 00:02:34.990 means every star gets a random birth time somewhere 00:02:34.990 --> 00:02:38.849 between 0 and 10 billion years ago. Some stars 00:02:38.849 --> 00:02:42.729 are ancient, some are newborn. Most fall somewhere 00:02:42.729 --> 00:02:47.150 in between. Every star that forms is assigned 00:02:47.150 --> 00:02:50.530 a mass. This is the most important choice in 00:02:50.530 --> 00:02:53.590 the entire simulation, because mass controls 00:02:53.590 --> 00:02:57.409 almost everything about a star's life. Its brightness, 00:02:57.789 --> 00:03:00.889 its temperature, and especially how long it lasts. 00:03:02.189 --> 00:03:05.349 We assign the mass randomly, but in accordance 00:03:05.349 --> 00:03:08.409 with some real -world parameters based on star 00:03:08.409 --> 00:03:12.389 formation, what astronomers call an initial mass 00:03:12.389 --> 00:03:17.150 function. We know most stars are small. Tiny 00:03:17.150 --> 00:03:21.289 red dwarfs dominate by sheer numbers. Sun -like 00:03:21.289 --> 00:03:25.370 stars are far less common, and massive brilliant 00:03:25.370 --> 00:03:29.750 stars are extremely rare. Once each star has 00:03:29.750 --> 00:03:32.610 a mass, we give it a lifetime using a simple 00:03:32.610 --> 00:03:36.590 rule of thumb. A star's main sequence lifetime 00:03:36.590 --> 00:03:40.909 scales roughly as its mass raised to the negative 00:03:40.909 --> 00:03:44.319 two and a half power. In plain language, that 00:03:44.319 --> 00:03:47.979 means doubling a star's mass shortens its life 00:03:47.979 --> 00:03:53.099 by more than half. Small stars can last hundreds 00:03:53.099 --> 00:03:56.120 of billions of years, longer than the universe 00:03:56.120 --> 00:04:00.219 has existed so far. Sun -like stars can live 00:04:00.219 --> 00:04:03.979 for about 10 billion years. Massive stars may 00:04:03.979 --> 00:04:07.039 only last a few million years before collapsing 00:04:07.039 --> 00:04:12.289 or exploding. With all this in mind our simulation 00:04:12.289 --> 00:04:15.530 ran and created half a million stars each with 00:04:15.530 --> 00:04:19.269 a birth time a mass and a fuel limited lifespan 00:04:19.269 --> 00:04:24.290 Then we fast forward time We stop the clock at 00:04:24.290 --> 00:04:27.670 10 billion years and ask one blunt question of 00:04:27.670 --> 00:04:30.589 every star Are you still on the main sequence 00:04:30.589 --> 00:04:34.829 or are you gone? The answers surprised me the 00:04:34.829 --> 00:04:39.800 first time I ran it Out of the 500 ,000 stars 00:04:39.800 --> 00:04:44.220 formed in this simulated galaxy, nearly 98 % 00:04:44.220 --> 00:04:48.040 are still alive after 10 billion years. That 00:04:48.040 --> 00:04:51.600 alone runs against our instincts. Stellar death 00:04:51.600 --> 00:04:55.100 feels dramatic and common, but statistically, 00:04:55.519 --> 00:04:59.019 it's actually rare. Most stars that ever form 00:04:59.019 --> 00:05:04.139 are long -term survivors. In the sim, every tiny 00:05:04.139 --> 00:05:08.509 red dwarf survives. Every small, faint star just 00:05:08.509 --> 00:05:11.910 keeps going, barely noticing the passage of billions 00:05:11.910 --> 00:05:16.769 of years. Sun -like stars mostly survive, too. 00:05:17.069 --> 00:05:20.389 In our test, all stars below about one solar 00:05:20.389 --> 00:05:24.269 mass are still shining at the end. But once we 00:05:24.269 --> 00:05:27.949 move above that into brighter, more massive stars, 00:05:28.370 --> 00:05:33.139 survival drops off fast. Only about half of stars 00:05:33.139 --> 00:05:36.060 between one and two solar masses make it to the 00:05:36.060 --> 00:05:39.779 present day. Among the bright, short -lived stars 00:05:39.779 --> 00:05:43.019 that dominate constellations, survival falls 00:05:43.019 --> 00:05:47.639 to just a few percent. And among the most massive 00:05:47.639 --> 00:05:51.160 stars of all, those destined to explode or collapse, 00:05:51.819 --> 00:05:54.560 less than one percent are still around when we 00:05:54.560 --> 00:05:58.899 stop the clock. And that leads to a grim conclusion. 00:05:59.259 --> 00:06:03.060 The stars that define the night sky are the least 00:06:03.060 --> 00:06:06.620 likely to still exist. We see their light because 00:06:06.620 --> 00:06:10.079 it takes thousands of years to arrive, but the 00:06:10.079 --> 00:06:14.240 stars creating that light may be long gone. The 00:06:14.240 --> 00:06:17.339 bright winter stars that feel timeless are anything 00:06:17.339 --> 00:06:20.860 but. They're rare, short -lived, and fleeting 00:06:20.860 --> 00:06:25.500 on galactic time scales. Meanwhile, the stars 00:06:25.500 --> 00:06:28.439 that actually dominate the galaxy, the quiet, 00:06:28.519 --> 00:06:32.379 patient red dwarves, are almost completely invisible 00:06:32.379 --> 00:06:37.180 to us, but they are still out there. Now, because 00:06:37.180 --> 00:06:40.120 this is a Monte Carlo experiment, I didn't stop 00:06:40.120 --> 00:06:43.860 there. I ran the entire simulation 20 different 00:06:43.860 --> 00:06:46.540 times, each with a different random universe. 00:06:47.360 --> 00:06:50.579 Different stars formed, different massive stars 00:06:50.579 --> 00:06:53.899 lived and died. The details changed slightly, 00:06:54.019 --> 00:06:58.079 but the conclusion really never did. Across all 00:06:58.079 --> 00:07:01.660 20 runs, the fraction of stars still alive after 00:07:01.660 --> 00:07:05.759 10 billion years was about 98%. With only tiny 00:07:05.759 --> 00:07:09.500 variations from run to run, the numbers barely 00:07:09.500 --> 00:07:13.560 moved. That tells us something important. This 00:07:13.560 --> 00:07:17.120 isn't a fluke, it's a structural feature of how 00:07:17.120 --> 00:07:21.459 stars work. And we can take this one step further. 00:07:21.639 --> 00:07:25.399 For the stars that did die, the simulation also 00:07:25.399 --> 00:07:29.120 tracks what they leave behind. Once a star is 00:07:29.120 --> 00:07:32.620 marked as dead, meaning its age exceeds its main 00:07:32.620 --> 00:07:36.600 sequence lifetime, the code classifies its remnant 00:07:36.600 --> 00:07:40.860 based on its initial mass. Stars below about 00:07:40.860 --> 00:07:45.120 8 solar masses become white dwarves. Those between 00:07:45.120 --> 00:07:48.860 roughly 8 and 20 solar masses become neutron 00:07:48.860 --> 00:07:53.149 stars. and the most massive stars become black 00:07:53.149 --> 00:07:58.149 holes. The overwhelming majority, more than 90%, 00:07:58.149 --> 00:08:02.470 become white dwarves, stellar cores quietly cooling 00:08:02.470 --> 00:08:06.329 toward invisibility. A much smaller fraction 00:08:06.329 --> 00:08:10.829 leave behind neutron stars, super dense but tiny 00:08:10.829 --> 00:08:15.509 star cores, and only a tiny handful, just a couple 00:08:15.509 --> 00:08:18.529 hundred out of half a million, end their lives 00:08:18.529 --> 00:08:22.689 as black holes. Which means something else quietly 00:08:22.689 --> 00:08:27.029 remarkable. Most stellar death is not explosive. 00:08:27.610 --> 00:08:30.709 The galaxy's graveyard is mostly filled with 00:08:30.709 --> 00:08:35.690 embers, not fireworks. So from a practical observing 00:08:35.690 --> 00:08:39.090 perspective, this explains something many stargazers 00:08:39.090 --> 00:08:42.649 eventually feel but rarely quantify. The night 00:08:42.649 --> 00:08:46.580 sky is a biased sample. It favors brightness, 00:08:46.840 --> 00:08:50.299 proximity, and youth. And from an analytical 00:08:50.299 --> 00:08:53.580 perspective, it tells us something deeper. When 00:08:53.580 --> 00:08:57.580 we talk about average or typical stars, we're 00:08:57.580 --> 00:09:00.820 almost never talking about the stars we can actually 00:09:00.820 --> 00:09:03.779 see. There's another interesting observation 00:09:03.779 --> 00:09:06.820 here that is a little shocking, and I can't take 00:09:06.820 --> 00:09:09.679 credit for it. As I was writing this episode, 00:09:09.779 --> 00:09:12.620 I shared this code with a listener, who just 00:09:12.620 --> 00:09:15.179 so happens to be my brother -in -law. Chris, 00:09:15.820 --> 00:09:18.759 and he had a striking comment regarding the results. 00:09:19.600 --> 00:09:22.940 You've heard me say the iconic Carl Sagan quote 00:09:22.940 --> 00:09:27.100 before, we're all made of star stuff. But if 00:09:27.100 --> 00:09:30.080 we're all made of elements from stars, and it's 00:09:30.080 --> 00:09:33.679 only the much larger stars that go nova and eject 00:09:33.679 --> 00:09:37.159 heavy elements into the cosmos, then Chris says, 00:09:37.600 --> 00:09:41.480 the stuff that makes us has to comprise a vanishingly 00:09:41.480 --> 00:09:44.500 small amount of the available matter in the universe. 00:09:45.279 --> 00:09:49.580 And he's right. We are rare, because the atoms 00:09:49.580 --> 00:09:53.419 that make us are statistically rare, and life 00:09:53.419 --> 00:09:56.080 like ours couldn't have existed in the early 00:09:56.080 --> 00:09:59.600 universe until those giant stars began seeding 00:09:59.600 --> 00:10:02.940 the cosmos with enough material to form rocky 00:10:02.940 --> 00:10:07.690 worlds and life itself. We are the inevitable 00:10:07.690 --> 00:10:11.190 outcome of a universe that runs long enough for 00:10:11.190 --> 00:10:16.090 complexity to accumulate. As always, if you'd 00:10:16.090 --> 00:10:18.809 like to run my little sim or study the code, 00:10:19.009 --> 00:10:22.029 I'll make it available at the show website. Just 00:10:22.029 --> 00:10:25.590 look for this episode's show notes. Alternately, 00:10:25.809 --> 00:10:28.350 I'll include a link that runs the code right 00:10:28.350 --> 00:10:31.210 in your web browser, in case you don't have Python 00:10:31.210 --> 00:10:35.460 and the required libraries. Now let's move from 00:10:35.460 --> 00:10:38.620 the realm of statistics to some actual stars 00:10:38.620 --> 00:10:41.440 that deserve our attention. I'm just going to 00:10:41.440 --> 00:10:44.799 mention an extremely small sample of some of 00:10:44.799 --> 00:10:48.220 the interesting stars we can see right now. A 00:10:48.220 --> 00:10:52.480 highlight reel, if you will. We start with Proxima 00:10:52.480 --> 00:10:55.860 Centauri, the star closest to Earth besides our 00:10:55.860 --> 00:10:59.840 own Sun. Its name just means the nearest, and 00:10:59.840 --> 00:11:03.840 that alone earns it attention. Proxima is a small, 00:11:04.080 --> 00:11:07.700 faint, red dwarf loosely bound to the Alpha Centauri 00:11:07.700 --> 00:11:11.840 system. It flares violently, bathing its planets 00:11:11.840 --> 00:11:15.580 in radiation, yet it hosts at least one Earth 00:11:15.580 --> 00:11:18.779 -mass world in the so -called habitable zone. 00:11:19.620 --> 00:11:22.620 Our nearest stellar neighbor is still more than 00:11:22.620 --> 00:11:26.220 four light years away. Close, astronomically 00:11:26.220 --> 00:11:29.820 speaking, but vast from an emotional standpoint. 00:11:30.379 --> 00:11:34.360 Then there's Barnard's star. This one is famous 00:11:34.360 --> 00:11:37.700 for its movement. Over the course of a human 00:11:37.700 --> 00:11:41.639 lifetime, Barnard's star visibly slides across 00:11:41.639 --> 00:11:45.779 the sky faster than any other known star. It's 00:11:45.779 --> 00:11:49.059 likely more than 10 billion years old, and it's 00:11:49.059 --> 00:11:53.059 simply passing through our neighborhood. Bernard's 00:11:53.059 --> 00:11:55.679 star quietly shattered the illusion that the 00:11:55.679 --> 00:11:59.340 constellations are fixed. The sky moves just 00:11:59.340 --> 00:12:05.039 very slowly. Now look south to Canopus. This 00:12:05.039 --> 00:12:08.080 is the second brightest star in the night sky, 00:12:08.320 --> 00:12:11.399 yet largely unfamiliar to northern observers. 00:12:12.399 --> 00:12:15.159 In fact, it's barely visible from where I live, 00:12:15.519 --> 00:12:17.820 and for those of you farther north, you may not 00:12:17.820 --> 00:12:22.080 be able to see it at all. Canopus has guided 00:12:22.080 --> 00:12:25.220 sailors for thousands of years and is still used 00:12:25.220 --> 00:12:29.639 for stellar navigation by spacecraft today. Some 00:12:29.639 --> 00:12:32.019 months back, a fan of the show mentioned to me 00:12:32.019 --> 00:12:35.600 that Canopus has a sci -fi connection. In the 00:12:35.600 --> 00:12:39.980 Dune saga, the ancestral home of House Atreides 00:12:39.980 --> 00:12:44.000 orbits Canopus. That choice isn't accidental. 00:12:44.409 --> 00:12:47.950 Canopus has long carried associations of authority, 00:12:48.330 --> 00:12:51.889 navigation, and distant power. And I have to 00:12:51.889 --> 00:12:54.210 thank our listener Mike for bringing this to 00:12:54.210 --> 00:12:58.789 my attention. Some stars earn attention not through 00:12:58.789 --> 00:13:02.110 proximity or brightness, but through reputation. 00:13:03.129 --> 00:13:06.789 Vega looks calm, clean, and reliable, and for 00:13:06.789 --> 00:13:11.710 a long time it was. 12 ,000 years ago, Vega was 00:13:11.710 --> 00:13:15.750 Earth's North Star. And it will be again in the 00:13:15.750 --> 00:13:19.769 far future as our planet's axis slowly wobbles. 00:13:20.190 --> 00:13:24.350 Even now, Vega spins so rapidly that it's flattened, 00:13:24.389 --> 00:13:28.850 hotter at its poles than at its equator. Then 00:13:28.850 --> 00:13:33.029 there's Antares. Its name means rival of Mars. 00:13:33.470 --> 00:13:37.009 And when it rises in summer skies, its red glow 00:13:37.009 --> 00:13:41.289 can fool the eye. Antares is a red supergiant 00:13:41.289 --> 00:13:44.809 nearing the end of its life. swollen and unstable, 00:13:45.409 --> 00:13:49.350 and shedding mass into space. If it replaced 00:13:49.350 --> 00:13:52.809 our sun, it would engulf the entire inner solar 00:13:52.809 --> 00:13:57.350 system. And finally, one that earns a more uneasy 00:13:57.350 --> 00:14:03.240 kind of fame, WR104. This triple star system 00:14:03.240 --> 00:14:06.159 is more than 8 ,000 light -years from Earth, 00:14:06.559 --> 00:14:10.679 and its primary star is a wolf rayet star, stripped 00:14:10.679 --> 00:14:13.620 of its outer layers and blasting material into 00:14:13.620 --> 00:14:16.980 space at extraordinary speed. It's wrapped in 00:14:16.980 --> 00:14:19.899 a spiral of dust known as the pinwheel nebula. 00:14:20.679 --> 00:14:23.899 The unease comes from its orientation and its 00:14:23.899 --> 00:14:28.320 relatively close proximity. The axis of WR was 00:14:28.320 --> 00:14:31.120 thought to be pointed roughly toward Earth, meaning 00:14:31.120 --> 00:14:34.100 that if it were to explode as a gamma ray burst, 00:14:34.659 --> 00:14:37.519 it could have consequences far beyond its immediate 00:14:37.519 --> 00:14:40.539 neighborhood, within just a few hundred thousand 00:14:40.539 --> 00:14:44.740 years. This existential threat earned WR the 00:14:44.740 --> 00:14:48.480 nickname of the Death Star. Although scientists 00:14:48.480 --> 00:14:51.720 now think the axial tilt doesn't quite line up 00:14:51.720 --> 00:14:54.159 with our solar system, it looks like we might 00:14:54.159 --> 00:14:58.460 be safe after all. Some stars don't just age 00:14:58.460 --> 00:15:02.100 or fade. They collapse, harden, and cross into 00:15:02.100 --> 00:15:06.740 a different category of existence. When a massive 00:15:06.740 --> 00:15:10.179 star runs out of fuel, gravity finally wins. 00:15:10.679 --> 00:15:14.039 The core implodes, protons and electrons are 00:15:14.039 --> 00:15:17.299 crushed together, and what's left behind is an 00:15:17.299 --> 00:15:22.000 extremely dense neutron star. Some neutron stars 00:15:22.000 --> 00:15:26.679 spin, and when they do, things get strange. A 00:15:26.679 --> 00:15:30.139 pulsar is a rotating neutron star that sweeps 00:15:30.139 --> 00:15:33.279 beams of radiation through space like a lighthouse. 00:15:34.279 --> 00:15:37.279 Every rotation sends a pulse toward Earth, which 00:15:37.279 --> 00:15:40.899 we receive at a regular interval. And some are 00:15:40.899 --> 00:15:45.029 so precise they rival atomic clocks. One of the 00:15:45.029 --> 00:15:48.509 most famous is the Crab Pulsar, the leftover 00:15:48.509 --> 00:15:52.029 core of a star that exploded in the year 1054. 00:15:52.950 --> 00:15:55.629 That explosion was recorded by astronomers in 00:15:55.629 --> 00:15:58.929 China, Japan and the Middle East, and it was 00:15:58.929 --> 00:16:02.629 visible in daylight for weeks. Nearly a thousand 00:16:02.629 --> 00:16:06.210 years later, the remnant is still spinning, broadcasting 00:16:06.210 --> 00:16:10.539 the death of a star across the galaxy. And, of 00:16:10.539 --> 00:16:13.559 course, the largest stars collapse into black 00:16:13.559 --> 00:16:16.779 holes, drawing in matter and energy that never 00:16:16.779 --> 00:16:20.779 escapes. We'll talk about stellar death in more 00:16:20.779 --> 00:16:23.899 detail in our next episode, but what's important 00:16:23.899 --> 00:16:27.080 here isn't just how violent these stars become. 00:16:27.620 --> 00:16:30.740 It's that they're normal outcomes. It's what 00:16:30.740 --> 00:16:33.559 happens when gravity is allowed to finish the 00:16:33.559 --> 00:16:51.820 job. After a quick break, we'll return with this 00:16:51.820 --> 00:16:54.580 week's Night Sky Report and some thoughts on 00:16:54.580 --> 00:16:57.460 the next two chapters of Night Watch. Stay with 00:16:57.460 --> 00:17:13.619 us. Welcome back. As we move into the middle 00:17:13.619 --> 00:17:16.859 of February, the night sky quietly gives us one 00:17:16.859 --> 00:17:20.059 of the best observing windows of the month. This 00:17:20.059 --> 00:17:23.259 week is defined by a disappearing moon, a slow 00:17:23.259 --> 00:17:26.519 motion gathering of planets, and a stretch of 00:17:26.519 --> 00:17:29.200 genuinely dark evenings that reward patience 00:17:29.200 --> 00:17:33.079 more than spectacle. This is not a week of fireworks, 00:17:33.420 --> 00:17:36.700 it's a week of alignment, absence, and restraint. 00:17:37.420 --> 00:17:40.619 Let's begin with the moon. We reach New Moon 00:17:40.619 --> 00:17:44.019 on February 17th, which places the darkest nights 00:17:44.019 --> 00:17:46.380 of the week right in the middle of this reporting 00:17:46.380 --> 00:17:49.759 window. Early in the week, the moon is a very 00:17:49.759 --> 00:17:52.799 thin waning crescent, rising late and staying 00:17:52.799 --> 00:17:57.059 mostly out of the evening sky. By the 17th, it's 00:17:57.059 --> 00:18:00.799 effectively absent altogether. Ideal conditions 00:18:00.799 --> 00:18:04.519 for deep sky observing, galaxy hunting, and revisiting 00:18:04.519 --> 00:18:07.319 faint clusters that usually struggle against 00:18:07.319 --> 00:18:11.339 moonlight. The moon returns quickly but delicately. 00:18:11.819 --> 00:18:15.700 From February 18th through the 21st, a thin waxing 00:18:15.700 --> 00:18:18.319 crescent appears low in the western sky just 00:18:18.319 --> 00:18:21.720 after sunset. These early crescents are soft 00:18:21.720 --> 00:18:24.880 and understated, and under steady skies you may 00:18:24.880 --> 00:18:28.099 notice earth shine, where sunlight reflected 00:18:28.099 --> 00:18:31.200 from earth faintly illuminates the moon's darkened 00:18:31.200 --> 00:18:34.789 hemisphere. A standout moment comes on the evening 00:18:34.789 --> 00:18:38.089 of February 19, when the young crescent moon 00:18:38.089 --> 00:18:41.450 passes in close conjunction with Saturn. The 00:18:41.450 --> 00:18:44.529 pairing sits low in the west just after sunset. 00:18:45.529 --> 00:18:49.009 Nearby, Mercury sits roughly five degrees to 00:18:49.009 --> 00:18:51.910 the south of Saturn. Mercury is climbing into 00:18:51.910 --> 00:18:54.089 one of its better evening appearances of the 00:18:54.089 --> 00:18:57.589 year, visible briefly after sunset if you have 00:18:57.589 --> 00:19:01.000 a clear western horizon. Binoculars can help, 00:19:01.220 --> 00:19:03.720 but the naked eye is often enough once you know 00:19:03.720 --> 00:19:07.119 where to look. Venus, despite being the brightest 00:19:07.119 --> 00:19:10.380 planet in the sky, is passing very close to the 00:19:10.380 --> 00:19:13.960 Sun during this period. As a result, it's largely 00:19:13.960 --> 00:19:17.680 lost in the glare and may be difficult or impossible 00:19:17.680 --> 00:19:21.559 to observe safely from most locations. Higher 00:19:21.559 --> 00:19:24.400 in the sky, Jupiter remains the anchor of the 00:19:24.400 --> 00:19:27.509 evening. It's visible as soon as the sky darkens 00:19:27.509 --> 00:19:30.210 and climbs into a commanding position in the 00:19:30.210 --> 00:19:33.970 southern sky as the night goes on. Jupiter stays 00:19:33.970 --> 00:19:37.289 up until after midnight and even a small telescope 00:19:37.289 --> 00:19:40.109 will show its cloud bands and several of its 00:19:40.109 --> 00:19:42.950 moons shifting position from night to night. 00:19:43.869 --> 00:19:46.690 Farther along the ecliptic, Saturn remains low 00:19:46.690 --> 00:19:49.450 in the west and increasingly difficult to see 00:19:49.450 --> 00:19:52.359 as the week progresses. but its encounter with 00:19:52.359 --> 00:19:55.440 the moon on the 19th makes it worth the effort. 00:19:56.079 --> 00:19:58.559 Uranus is still accessible in the early evening 00:19:58.559 --> 00:20:02.240 near the Pleiades in Taurus, appearing as a faint 00:20:02.240 --> 00:20:05.640 bluish -green point in binoculars or a small 00:20:05.640 --> 00:20:08.680 scope. With the moon out of the way for much 00:20:08.680 --> 00:20:11.980 of this period, the deep sky quietly takes center 00:20:11.980 --> 00:20:15.079 stage. The Pleiades are especially rewarding 00:20:15.079 --> 00:20:18.079 this week under moonless skies, revealing layers 00:20:18.079 --> 00:20:21.180 of stars and binoculars that are easy to miss 00:20:21.180 --> 00:20:24.480 when the moon is brighter. Dark sky observers 00:20:24.480 --> 00:20:27.319 may also want to use this stretch to hunt faint 00:20:27.319 --> 00:20:30.500 galaxies or revisit some of the clusters we've 00:20:30.500 --> 00:20:40.490 mentioned in the past few episodes. This week 00:20:40.490 --> 00:20:43.609 in the Star Trails Book Club, we're reading chapters 00:20:43.609 --> 00:20:48.369 four and five out of Night Watch. Titled Stars 00:20:48.369 --> 00:20:51.789 for All Seasons, chapter four is a meaty portion 00:20:51.789 --> 00:20:54.109 of the book that does a lot of heavy lifting. 00:20:54.809 --> 00:20:57.450 At first glance, this chapter feels a little 00:20:57.450 --> 00:21:00.529 old school. Dickinson spends a good amount of 00:21:00.529 --> 00:21:03.450 time with printed star charts, the kind you'd 00:21:03.450 --> 00:21:05.930 expect to see folded in the back of a book or 00:21:05.930 --> 00:21:09.539 laminated for use in the field. In an era of 00:21:09.539 --> 00:21:12.319 phone apps like Stellarium, these charts can 00:21:12.319 --> 00:21:16.000 feel quaint, almost ceremonial, but Dickinson 00:21:16.000 --> 00:21:19.339 makes a strong case for them. Printed charts 00:21:19.339 --> 00:21:22.519 don't kill your night vision, and most importantly, 00:21:22.779 --> 00:21:25.900 they force you to learn the sky rather than outsource 00:21:25.900 --> 00:21:29.799 it. Interestingly, Dickinson introduces two kinds 00:21:29.799 --> 00:21:33.960 of star charts. One set shows an average sky, 00:21:34.160 --> 00:21:37.279 not pristine, not heavily light polluted, but 00:21:37.279 --> 00:21:39.859 something close to what many backyard observers 00:21:39.859 --> 00:21:44.000 actually experience. The other set is more traditional, 00:21:44.400 --> 00:21:47.660 black on white, constellations connected by lines, 00:21:48.259 --> 00:21:51.940 labeled stars, and the ecliptic plane drawn across 00:21:51.940 --> 00:21:55.180 the chart to show where the planets travel. It's 00:21:55.180 --> 00:21:58.549 much more detailed. These charts aren't meant 00:21:58.549 --> 00:22:01.390 to be memorized, and Dickinson is pretty clear 00:22:01.390 --> 00:22:04.150 about that. There's simply too much information 00:22:04.150 --> 00:22:07.210 here to absorb in one pass. This is a chapter 00:22:07.210 --> 00:22:10.009 you come back to as your familiarity with the 00:22:10.009 --> 00:22:13.509 sky deepens. One of the most striking explanations 00:22:13.509 --> 00:22:16.049 in this chapter comes when Dickinson talks about 00:22:16.049 --> 00:22:19.529 the Milky Way. When we look up and see that misty 00:22:19.529 --> 00:22:22.349 cloud -like band, what we're really seeing is 00:22:22.349 --> 00:22:25.509 perspective. We're looking sideways through the 00:22:25.509 --> 00:22:29.210 disk of our galaxy into spiral arms packed with 00:22:29.210 --> 00:22:33.589 stars. Those stars are so numerous and so distant 00:22:33.589 --> 00:22:36.269 that our eyes can't resolve them individually. 00:22:36.869 --> 00:22:39.730 Instead, they blur together into that familiar 00:22:39.730 --> 00:22:43.369 river of light. The Milky Way isn't a cloud at 00:22:43.369 --> 00:22:47.130 all. It's a crowd. Dickinson also does a nice 00:22:47.130 --> 00:22:50.549 job reminding us that brightness is deceptive. 00:22:50.829 --> 00:22:54.390 Take Deneb, for example, one of the stars of 00:22:54.390 --> 00:22:57.609 the Summer Triangle. It may be one of the largest 00:22:57.609 --> 00:23:00.950 and most luminous stars in the entire Milky Way, 00:23:01.329 --> 00:23:05.369 but it's more than 1600 light -years away. Because 00:23:05.369 --> 00:23:07.829 of that distance, it appears dimmer than its 00:23:07.829 --> 00:23:11.569 closer companions Vega and Altair, even though 00:23:11.569 --> 00:23:14.589 it utterly dwarfs them in true size and power. 00:23:15.279 --> 00:23:17.859 Throughout the chapter, Dickinson breaks the 00:23:17.859 --> 00:23:20.880 sky down by season, and one observation stood 00:23:20.880 --> 00:23:25.480 out to me, autumn. According to Dickinson, autumn 00:23:25.480 --> 00:23:28.740 actually contains fewer distinctive star patterns 00:23:28.740 --> 00:23:31.400 than the other seasons. It's not that the sky 00:23:31.400 --> 00:23:34.259 is empty, but that it lacks the bold, obvious 00:23:34.259 --> 00:23:37.980 shapes we associate with winter or summer. He 00:23:37.980 --> 00:23:41.240 mentions the region called the Cetus Void, an 00:23:41.240 --> 00:23:44.420 area with no first or second magnitude stars 00:23:44.420 --> 00:23:48.079 at all. Winter, on the other hand, often feels 00:23:48.079 --> 00:23:50.960 special to observers, but Dickinson points out 00:23:50.960 --> 00:23:54.579 something subtle. Winter skies aren't necessarily 00:23:54.579 --> 00:23:57.819 better for observing. What they do have is more 00:23:57.819 --> 00:24:01.039 bright stars, which gives the impression of richness 00:24:01.039 --> 00:24:04.940 and clarity. This is also where Dickinson emphasizes 00:24:04.940 --> 00:24:08.349 something many of us take for granted. Orion's 00:24:08.349 --> 00:24:12.170 belt. Those three stars are actually unusual. 00:24:12.910 --> 00:24:15.269 Dickinson notes that they're the only example 00:24:15.269 --> 00:24:18.029 of three stars of that brightness appearing this 00:24:18.029 --> 00:24:21.569 close together in the sky. It's not just iconic 00:24:21.569 --> 00:24:25.589 by tradition, it's genuinely rare. Finally, the 00:24:25.589 --> 00:24:28.269 chapter brings us back to the Milky Way, this 00:24:28.269 --> 00:24:31.589 time in winter. The Milky Way appears dimmer 00:24:31.589 --> 00:24:34.680 in winter because of where we're looking. In 00:24:34.680 --> 00:24:37.660 winter, our nighttime view points away from the 00:24:37.660 --> 00:24:40.559 galactic center, toward the outer edges of the 00:24:40.559 --> 00:24:43.700 galaxy, where stars are more sparsely distributed. 00:24:44.299 --> 00:24:47.619 It's all about our orientation. Nothing in the 00:24:47.619 --> 00:24:51.299 sky is static. The seasons don't just bring about 00:24:51.299 --> 00:24:54.380 weather changes, they change our angle on the 00:24:54.380 --> 00:24:57.579 universe. What we see depends on where we're 00:24:57.579 --> 00:25:01.279 standing, and where we're looking. In Chapter 00:25:01.279 --> 00:25:04.880 5, Observing Tools and Techniques, Dickinson 00:25:04.880 --> 00:25:07.880 shifts the focus away from charts and constellations 00:25:07.880 --> 00:25:11.579 to the actual tools of observation. And one of 00:25:11.579 --> 00:25:14.539 the first things he does is quietly decenter 00:25:14.539 --> 00:25:18.079 the importance of the telescope. Dickinson spends 00:25:18.079 --> 00:25:20.539 a surprising amount of time reminding viewers 00:25:20.539 --> 00:25:23.640 that astronomy doesn't begin with magnification. 00:25:24.079 --> 00:25:27.440 It begins with patience, dark adaptation, and 00:25:27.440 --> 00:25:30.579 learning how your eyes work in low light. He 00:25:30.579 --> 00:25:34.200 makes a strong case for the naked eye and binoculars 00:25:34.200 --> 00:25:37.660 not as beginner substitutes But as serious observing 00:25:37.660 --> 00:25:41.259 tools that preserve context and teach you how 00:25:41.259 --> 00:25:44.680 the sky fits together There's also a recurring 00:25:44.680 --> 00:25:47.680 theme of expectation management running through 00:25:47.680 --> 00:25:51.400 this chapter Dickinson is very clear that the 00:25:51.400 --> 00:25:55.119 sky does not look like photographs Nebula don't 00:25:55.119 --> 00:25:58.420 glow in color galaxies don't leap out of the 00:25:58.420 --> 00:26:02.369 eyepiece Most deep -sky objects are faint, subtle, 00:26:02.730 --> 00:26:05.349 and easy to miss unless you know how to look, 00:26:05.670 --> 00:26:08.549 and unless you accept them on their own terms. 00:26:09.410 --> 00:26:11.869 And that leads directly into one of the most 00:26:11.869 --> 00:26:15.309 memorable parts of the chapter. But first, a 00:26:15.309 --> 00:26:18.250 personal anecdote, and I think many of you will 00:26:18.250 --> 00:26:21.150 be able to relate to this. When I was in the 00:26:21.150 --> 00:26:24.250 seventh grade, I received, for Christmas, a shiny 00:26:24.250 --> 00:26:28.220 new Jason refractor. which seemingly came with 00:26:28.220 --> 00:26:31.980 every bell and whistle possible, except actually 00:26:31.980 --> 00:26:35.319 using it was beyond frustrating owing to a rickety 00:26:35.319 --> 00:26:39.920 tripod, wobbly mount, stiff focusers, and a nearly 00:26:39.920 --> 00:26:43.460 useless finder scope. After weeks of practice, 00:26:43.619 --> 00:26:46.319 I was able to tease out decent views of Jupiter, 00:26:46.720 --> 00:26:50.099 Venus, and Saturn, but not much else, and only 00:26:50.099 --> 00:26:53.059 after many minutes of frustration trying to acquire 00:26:53.059 --> 00:26:56.700 my targets. Dickinson has a name for these cheap 00:26:56.700 --> 00:27:00.220 telescopes that flood big -box stores every holiday 00:27:00.220 --> 00:27:04.200 season. He calls them Christmas trash scopes, 00:27:04.640 --> 00:27:07.700 because they so often sabotage a beginner's first 00:27:07.700 --> 00:27:12.099 experience. In many cases, the optics themselves 00:27:12.099 --> 00:27:15.740 aren't terrible. The real problem is almost always 00:27:15.740 --> 00:27:18.980 the mount. These scopes are perched on shaky, 00:27:19.380 --> 00:27:21.779 underbuilt tripods that wobble when you touch 00:27:21.779 --> 00:27:25.299 them, vibrate when you focus, and refuse to stay 00:27:25.299 --> 00:27:28.579 pointed where you aim them. Add in low -quality 00:27:28.579 --> 00:27:31.880 eyepieces, and even bright objects become frustrating 00:27:31.880 --> 00:27:35.940 to observe. This is why Chapter 5 keeps circling 00:27:35.940 --> 00:27:39.430 back to simplicity. A modest instrument on a 00:27:39.430 --> 00:27:42.130 solid mount, or even a good pair of binoculars, 00:27:42.569 --> 00:27:45.269 will almost always create a better experience 00:27:45.269 --> 00:27:48.250 than a flashy telescope that can't hold still. 00:27:49.470 --> 00:27:52.069 And, interestingly, Dickinson doesn't exclude 00:27:52.069 --> 00:27:55.509 the use of so -called smart scopes or go -to 00:27:55.509 --> 00:27:58.970 mounts. He said he once discouraged people from 00:27:58.970 --> 00:28:01.009 using them but realized that in the interest 00:28:01.009 --> 00:28:03.950 of getting up and observing fast, particularly 00:28:03.950 --> 00:28:06.930 in areas with a challenging sky, These smart 00:28:06.930 --> 00:28:11.289 scopes can be a godsend. This chapter also provides 00:28:11.289 --> 00:28:15.170 an excellent survey of scope types, reflector 00:28:15.170 --> 00:28:19.450 vs. refractor, dobsonian mounts vs. equatorial 00:28:19.450 --> 00:28:23.049 mounts, and so on, along with the pros and cons 00:28:23.049 --> 00:28:26.150 of it all. It's quite a technical chapter but 00:28:26.150 --> 00:28:28.349 essential reading if you're looking to purchase 00:28:28.349 --> 00:28:31.369 an instrument. As always, if you have any thoughts 00:28:31.369 --> 00:28:33.769 on these chapters, please let me know over at 00:28:33.769 --> 00:28:36.369 the show website. I'd love to be able to share 00:28:36.369 --> 00:28:38.990 some of your reflections on a future episode. 00:28:39.390 --> 00:28:42.210 We'll cover the next two chapters two weeks from 00:28:42.210 --> 00:28:48.730 now. That's going to do it for this week. If 00:28:48.730 --> 00:28:51.009 you found this episode interesting, please share 00:28:51.009 --> 00:28:53.849 it with a friend who might enjoy it. The easiest 00:28:53.849 --> 00:28:56.869 way to do that is by sending folks to our website, 00:28:57.230 --> 00:29:00.579 StarTrails .Show. And if you'd like to support 00:29:00.579 --> 00:29:03.220 the show, use the link on the site to buy me 00:29:03.220 --> 00:29:06.579 a coffee. Be sure to follow Star Trails on Blue 00:29:06.579 --> 00:29:10.000 Sky and YouTube. Links are in the show notes. 00:29:10.700 --> 00:29:13.440 Until we meet again beneath the stars, clear 00:29:13.440 --> 00:29:14.279 skies everyone.