WEBVTT 00:00:07.820 --> 00:00:10.199 Howdy Stargazers, and welcome to this episode 00:00:10.199 --> 00:00:13.500 of Star Trails. My name is Drew, and I'll be 00:00:13.500 --> 00:00:16.440 your guide to the night sky for the week of February 00:00:16.440 --> 00:00:20.760 the 8th to the 14th. This week we continue our 00:00:20.760 --> 00:00:24.300 exploration of the lives of stars, in particular 00:00:24.300 --> 00:00:27.399 the ones alive right now that are shaping the 00:00:27.399 --> 00:00:30.879 solar systems, nebula and even galaxies that 00:00:30.879 --> 00:00:33.619 surround them. We'll talk about how they're born 00:00:33.619 --> 00:00:37.240 and how they live their lives. Later in the show 00:00:37.240 --> 00:00:39.960 we'll take a look at this week's sky and I'll 00:00:39.960 --> 00:00:43.320 demystify the phenomenon of the so -called planetary 00:00:43.320 --> 00:00:46.859 parade. One of those is forming right now, and 00:00:46.859 --> 00:00:50.020 it could make for some interesting views. Whether 00:00:50.020 --> 00:00:52.539 you're tuning in from the backyard or the balcony, 00:00:52.859 --> 00:00:55.579 I'm glad you're here, so grab a comfortable spot 00:00:55.579 --> 00:01:00.200 under the night sky and let's get started. When 00:01:00.200 --> 00:01:03.000 we look up at the night sky, it's easy to think 00:01:03.000 --> 00:01:07.359 of stars as static, fixed points of light that 00:01:07.359 --> 00:01:11.900 simply exist unchanged night after night. But 00:01:11.900 --> 00:01:18.739 stars are anything but passive. While they're 00:01:18.739 --> 00:01:22.920 alive, right now, stars are shaping their surroundings, 00:01:23.480 --> 00:01:26.739 organizing matter, and quietly steering the future 00:01:26.739 --> 00:01:29.879 of the universe. They're not just objects in 00:01:29.879 --> 00:01:34.500 space. They're active agents within it. Stars 00:01:34.500 --> 00:01:38.519 also don't exist in isolation. That sense of 00:01:38.519 --> 00:01:41.640 solitude is mostly an illusion created by distance. 00:01:42.359 --> 00:01:45.819 Most stars are born inside enormous clouds of 00:01:45.819 --> 00:01:48.799 cold gas and dust drifting through galaxies. 00:01:50.239 --> 00:01:53.359 These clouds are often called stellar nurseries, 00:01:53.780 --> 00:01:57.040 and while that name emphasizes beginnings, what 00:01:57.040 --> 00:01:59.840 matters for tonight is what happens after stars 00:01:59.840 --> 00:02:03.989 appear. Once stars form, they don't politely 00:02:03.989 --> 00:02:07.510 step aside and let the nursery continue undisturbed. 00:02:07.750 --> 00:02:11.770 They interfere. A stellar nursery becomes an 00:02:11.770 --> 00:02:14.590 active construction site the moment stars turn 00:02:14.590 --> 00:02:18.569 on. Young stars pour out radiation and stellar 00:02:18.569 --> 00:02:22.750 winds. Their light heats nearby gas. Their pressure 00:02:22.750 --> 00:02:26.449 pushes material away. Cavities open up inside 00:02:26.449 --> 00:02:30.180 the cloud. Dense regions are eroded. and other 00:02:30.180 --> 00:02:34.039 regions are compressed. In some places, star 00:02:34.039 --> 00:02:38.159 formation is shut down entirely as gas is dispersed. 00:02:38.900 --> 00:02:41.960 In others, new stars are triggered as material 00:02:41.960 --> 00:02:46.460 is squeezed just enough to collapse. Stars don't 00:02:46.460 --> 00:02:49.759 just come from their environments. They immediately 00:02:49.759 --> 00:02:54.960 begin reshaping them. A nearby and famous example 00:02:54.960 --> 00:02:58.759 of this process is the Orion Nebula. When you 00:02:58.759 --> 00:03:01.219 look at Orion through a telescope, you're not 00:03:01.219 --> 00:03:04.500 just seeing something ancient or finished. You're 00:03:04.500 --> 00:03:08.599 seeing an ongoing process. Massive young stars 00:03:08.599 --> 00:03:11.680 flood their surroundings with intense ultraviolet 00:03:11.680 --> 00:03:15.639 light, sculpting glowing walls of gas and carving 00:03:15.639 --> 00:03:20.319 dark lanes where dust blocks the light. Some 00:03:20.319 --> 00:03:23.240 regions are being cleared out, while others are 00:03:23.240 --> 00:03:27.699 actively forming new stars. Orion is not a snapshot 00:03:27.699 --> 00:03:31.300 of the past, it's stellar influence unfolding 00:03:31.300 --> 00:03:35.319 in real time. Another striking example is the 00:03:35.319 --> 00:03:39.319 Eagle Nebula, home to the famous Pillars of Creation. 00:03:39.900 --> 00:03:43.159 Those towering columns of gas are not quietly 00:03:43.159 --> 00:03:47.199 building stars in isolation. They're being actively 00:03:47.199 --> 00:03:50.919 eroded by radiation from nearby massive stars. 00:03:51.819 --> 00:03:55.020 The pillars themselves are temporary structures, 00:03:55.620 --> 00:03:58.319 slowly being destroyed by the very environment 00:03:58.319 --> 00:04:02.680 that surrounds them. This is what stellar influence 00:04:02.680 --> 00:04:06.259 looks like, creation and destruction unfolding 00:04:06.259 --> 00:04:12.800 together over millions of years. Stars also rarely 00:04:12.800 --> 00:04:16.839 form alone. Most are born in groups called star 00:04:16.839 --> 00:04:20.120 clusters, and these clusters come in two very 00:04:20.120 --> 00:04:24.660 different flavors. Open clusters are loose, relatively 00:04:24.660 --> 00:04:27.800 young groups of stars that form together inside 00:04:27.800 --> 00:04:31.480 stellar nurseries. Their gravity is weak, and 00:04:31.480 --> 00:04:34.480 over time the stars drift apart, spreading into 00:04:34.480 --> 00:04:38.259 the galaxy. These clusters let us watch stellar 00:04:38.259 --> 00:04:42.920 evolution in its early and middle stages. A beautiful 00:04:42.920 --> 00:04:45.759 example is the Pleiades, visible to the naked 00:04:45.759 --> 00:04:48.920 eye as a small dipper -shaped group of stars. 00:04:49.199 --> 00:04:52.800 It's a young cluster still interacting with leftover 00:04:52.800 --> 00:04:57.300 dust from its birth cloud. Another is the Hyades, 00:04:57.519 --> 00:05:00.579 an older, more spread out cluster that shows 00:05:00.579 --> 00:05:03.579 what happens as gravity slowly loses its grip 00:05:03.579 --> 00:05:08.300 and a stellar family dissolves. Open clusters 00:05:08.300 --> 00:05:11.459 remind us that many of the stars we see, including 00:05:11.459 --> 00:05:15.199 our own sun, likely began life with siblings 00:05:15.199 --> 00:05:17.540 that are now scattered across the Milky Way. 00:05:18.790 --> 00:05:21.670 Globular clusters, on the other hand, are something 00:05:21.670 --> 00:05:25.670 else entirely. These are dense, ancient spheres 00:05:25.670 --> 00:05:29.189 containing hundreds of thousands of stars, all 00:05:29.189 --> 00:05:33.069 bound tightly by gravity. They formed early in 00:05:33.069 --> 00:05:35.829 the galaxy's history and have remained intact 00:05:35.829 --> 00:05:40.720 for billions of years. Inside them, stars are 00:05:40.720 --> 00:05:43.660 packed so closely that stellar interactions are 00:05:43.660 --> 00:05:46.579 common, and the environment is far more crowded 00:05:46.579 --> 00:05:50.379 than anything near our sun. One of the finest 00:05:50.379 --> 00:05:52.779 examples visible from the Northern Hemisphere 00:05:52.779 --> 00:05:56.519 is the Hercules Cluster. Through binoculars or 00:05:56.519 --> 00:05:59.519 a telescope, it appears as a dense glowing ball 00:05:59.519 --> 00:06:04.240 of stars, an entire ancient stellar city suspended 00:06:04.240 --> 00:06:08.360 in space. Globular clusters show us what happens 00:06:08.360 --> 00:06:11.839 when stars live their lives together for immense 00:06:11.839 --> 00:06:15.319 spans of time. They're reminders that stellar 00:06:15.319 --> 00:06:18.959 evolution is often a communal process, not a 00:06:18.959 --> 00:06:22.819 solitary one. Clusters also reveal something 00:06:22.819 --> 00:06:26.579 fundamental about stars. When all stars in a 00:06:26.579 --> 00:06:29.060 cluster form at the same time, the differences 00:06:29.060 --> 00:06:31.720 we see between them are not about age, they're 00:06:31.720 --> 00:06:35.779 about mass. Mass determines how a star behaves 00:06:35.779 --> 00:06:39.819 while it's alive. Massive stars burn hot and 00:06:39.819 --> 00:06:42.920 fast, with fusion running furiously in their 00:06:42.920 --> 00:06:47.279 cores. They shine brilliantly but briefly, sometimes 00:06:47.279 --> 00:06:51.339 for only a few million years. Smaller stars are 00:06:51.339 --> 00:06:55.480 different. Red dwarfs, the smallest stars capable 00:06:55.480 --> 00:06:58.560 of sustaining fusion, burn their fuel slowly 00:06:58.560 --> 00:07:02.050 and efficiently. They mix their hydrogen throughout 00:07:02.050 --> 00:07:04.910 their interiors, wasting very little, and as 00:07:04.910 --> 00:07:09.689 a result, they endure. Based on how slowly red 00:07:09.689 --> 00:07:13.009 dwarfs consume their fuel, astronomers calculate 00:07:13.009 --> 00:07:16.810 lifespans not in billions of years, but in trillions. 00:07:17.610 --> 00:07:22.250 Ten trillion years, and possibly more. The universe 00:07:22.250 --> 00:07:26.730 itself is only about 13 .8 billion years old. 00:07:26.970 --> 00:07:30.250 So how can we possibly know that some stars will 00:07:30.250 --> 00:07:32.910 live for trillions of years when the universe 00:07:32.910 --> 00:07:36.389 hasn't even been around that long? The answer 00:07:36.389 --> 00:07:39.050 is that astronomy doesn't rely on weighting. 00:07:39.149 --> 00:07:45.189 It relies on physics. We understand how stars 00:07:45.189 --> 00:07:48.350 work at a fundamental level. How much fuel they 00:07:48.350 --> 00:07:51.980 contain. How fast they burn it. and how efficiently 00:07:51.980 --> 00:07:55.319 that energy is produced. Once you know those 00:07:55.319 --> 00:07:57.879 things, you don't need to watch the entire lifespan 00:07:57.879 --> 00:08:00.480 play out any more than you need to wait for a 00:08:00.480 --> 00:08:03.459 candle to burn out to estimate how long it will 00:08:03.459 --> 00:08:08.959 last. There's also an important piece of observational 00:08:08.959 --> 00:08:12.699 evidence. Not a single red dwarf has ever been 00:08:12.699 --> 00:08:16.560 observed to die of old age. We see young red 00:08:16.560 --> 00:08:20.670 dwarfs, old ones, and ancient ones. but no red 00:08:20.670 --> 00:08:23.709 dwarf remnants created through normal stellar 00:08:23.709 --> 00:08:27.310 aging. The universe simply hasn't been around 00:08:27.310 --> 00:08:30.550 long enough for that to happen. The absence isn't 00:08:30.550 --> 00:08:34.909 a mystery, it's a confirmation. While stars are 00:08:34.909 --> 00:08:38.409 alive, they're also busy building systems. When 00:08:38.409 --> 00:08:41.509 a star forms, it's surrounded by a rotating disk 00:08:41.509 --> 00:08:46.659 of gas and dust. Inside that disk, material collides 00:08:46.659 --> 00:08:49.720 and sticks together, eventually forming planets. 00:08:51.120 --> 00:08:54.360 Stars don't just host planets, they define the 00:08:54.360 --> 00:08:58.860 architecture of entire solar systems. A star's 00:08:58.860 --> 00:09:02.679 gravity sets orbital paths, its radiation shapes 00:09:02.679 --> 00:09:06.259 atmospheres, and its early activity determines 00:09:06.259 --> 00:09:09.820 which planets survive and which never fully form. 00:09:10.159 --> 00:09:15.820 Stars also define where life might exist. A star's 00:09:15.820 --> 00:09:18.259 brightness determines where liquid water could 00:09:18.259 --> 00:09:21.240 persist on a planet's surface, but that zone 00:09:21.240 --> 00:09:25.559 is not fixed. As stars age, they slowly brighten 00:09:25.559 --> 00:09:29.379 and the habitable zone moves outward. Planets 00:09:29.379 --> 00:09:33.299 drift into and out of favorable conditions, not 00:09:33.299 --> 00:09:36.299 because they move, but because their star evolves. 00:09:37.070 --> 00:09:40.389 Beyond planets, stars provide something even 00:09:40.389 --> 00:09:44.350 more fundamental, persistent energy. Not just 00:09:44.350 --> 00:09:47.529 light, but long -lasting energy gradients that 00:09:47.529 --> 00:09:51.649 keep chemistry alive, atmospheres dynamic, and 00:09:51.649 --> 00:09:55.429 complexity from running down too quickly. Stars 00:09:55.429 --> 00:09:58.690 act as long -burning engines that hold complexity 00:09:58.690 --> 00:10:02.490 open, locally and temporarily, but long enough 00:10:02.490 --> 00:10:10.690 to matter. Zoom out even further and stars help 00:10:10.690 --> 00:10:14.409 define the structure of entire galaxies. They 00:10:14.409 --> 00:10:18.730 trace spiral arms, outline galactic discs, and 00:10:18.730 --> 00:10:22.070 mark where gas collects and where it doesn't. 00:10:22.470 --> 00:10:25.269 Galaxies don't look the way they do despite stars, 00:10:25.490 --> 00:10:30.789 they look that way because of them. This leads 00:10:30.789 --> 00:10:34.460 to a quiet realization beneath all this. We're 00:10:34.460 --> 00:10:37.220 living in a very particular chapter of cosmic 00:10:37.220 --> 00:10:41.320 history. Star formation is still active. Bright, 00:10:41.559 --> 00:10:45.440 sun -like stars are common. Heavy elements are 00:10:45.440 --> 00:10:49.980 abundant. Planetary systems are widespread. In 00:10:49.980 --> 00:10:52.899 the far future, the universe will belong to small, 00:10:53.179 --> 00:10:57.139 dim, long -lived stars, glowing faintly for trillions 00:10:57.139 --> 00:11:01.539 of years while galaxies slowly fade. Right now 00:11:01.539 --> 00:11:05.539 is a relatively bright chapter. Stars are still 00:11:05.539 --> 00:11:08.960 alive in large numbers, still energetic, still 00:11:08.960 --> 00:11:11.759 shaping their environments. In other words, they're 00:11:11.759 --> 00:11:15.700 still doing their work. Stars are not static 00:11:15.700 --> 00:11:19.299 points of light. They heat gas, sculpt nebula, 00:11:19.740 --> 00:11:23.139 regulate star formation, build solar systems, 00:11:23.340 --> 00:11:26.980 and define where complexity can exist. They don't 00:11:26.980 --> 00:11:31.080 simply shine. They organize matter. patiently, 00:11:31.559 --> 00:11:34.840 collectively, and over immense spans of time. 00:11:35.820 --> 00:11:53.679 And all of that is happening right now. After 00:11:53.679 --> 00:11:56.159 a quick break, we'll check in with what you can 00:11:56.159 --> 00:11:59.480 see in the night sky this week. Stay with us. 00:12:11.879 --> 00:12:15.700 Welcome back! This week the moon is moving through 00:12:15.700 --> 00:12:18.820 its waning gibbous phase and will pass third 00:12:18.820 --> 00:12:22.500 quarter on February the 9th. As the week goes 00:12:22.500 --> 00:12:25.720 on, the moon rises later each night, which means 00:12:25.720 --> 00:12:29.820 darker skies earlier in the evening. By midweek, 00:12:29.960 --> 00:12:32.440 you'll have a more generous window for observing 00:12:32.440 --> 00:12:35.419 before moonlight becomes an issue, especially 00:12:35.419 --> 00:12:38.940 if you're heading out shortly after sunset. You 00:12:38.940 --> 00:12:41.700 may hear this week described in headlines as 00:12:41.700 --> 00:12:45.399 a so -called parade of planets and rather than 00:12:45.399 --> 00:12:47.679 dismissing that outright it's actually a good 00:12:47.679 --> 00:12:50.500 opportunity to explain what's really going on 00:12:50.500 --> 00:12:53.980 and Why planets so often appear in the same part 00:12:53.980 --> 00:12:57.940 of the sky? All of the major planets in our solar 00:12:57.940 --> 00:13:01.279 system orbit the Sun in nearly the same flat 00:13:01.279 --> 00:13:05.019 plane From Earth that plane projects onto the 00:13:05.019 --> 00:13:09.330 sky as a gentle arc called the ecliptic. It's 00:13:09.330 --> 00:13:12.169 the same path the sun appears to follow across 00:13:12.169 --> 00:13:15.529 the sky over the course of a year, and it's also 00:13:15.529 --> 00:13:18.570 where the moon and planets spend almost all of 00:13:18.570 --> 00:13:21.769 their time. So when several planets are visible 00:13:21.769 --> 00:13:24.490 at once, they aren't lining up by coincidence. 00:13:24.809 --> 00:13:27.590 They're simply tracing the same shared highway 00:13:27.590 --> 00:13:31.490 across the sky. This week, that highway runs 00:13:31.490 --> 00:13:34.889 low across the western and southwestern sky after 00:13:34.889 --> 00:13:38.399 sunset. Jupiter is the easiest place to start, 00:13:38.779 --> 00:13:41.720 bright, steady, and well above the horizon as 00:13:41.720 --> 00:13:46.059 twilight fades. Saturn sits much lower, closer 00:13:46.059 --> 00:13:49.159 to the horizon, and requires a bit more patience 00:13:49.159 --> 00:13:52.820 as it lingers in the glow of sunset. Mercury 00:13:52.820 --> 00:13:55.799 makes only a brief appearance very low in the 00:13:55.799 --> 00:13:58.559 west, rewarding observers who look early and 00:13:58.559 --> 00:14:02.360 know where to scan. That's why planetary parades 00:14:02.360 --> 00:14:05.200 tend to be quieter than the headlines suggest. 00:14:05.480 --> 00:14:08.419 The planets aren't stacked in a dramatic row 00:14:08.419 --> 00:14:11.340 and they won't leap out at you unless you already 00:14:11.340 --> 00:14:14.259 understand the layout of the sky. What you're 00:14:14.259 --> 00:14:17.740 really seeing is the ecliptic itself, the architecture 00:14:17.740 --> 00:14:21.080 of the solar system made visible. If you step 00:14:21.080 --> 00:14:24.179 outside and slowly trace that gentle line across 00:14:24.179 --> 00:14:27.179 the sky from west towards south and then east, 00:14:27.759 --> 00:14:30.259 you're following the same plane planets have 00:14:30.259 --> 00:14:33.620 orbited in for billions of years. Once you recognize 00:14:33.620 --> 00:14:35.960 it, you'll start seeing it everywhere, in where 00:14:35.960 --> 00:14:39.100 planets rise, where the moon travels, and even 00:14:39.100 --> 00:14:43.100 where eclipses become possible. Once twilight 00:14:43.100 --> 00:14:46.139 fades, this week is a great time to explore some 00:14:46.139 --> 00:14:49.440 quieter corners of the winter sky, objects that 00:14:49.440 --> 00:14:52.440 don't always get top billing but reward a little 00:14:52.440 --> 00:14:56.320 patience. In Gemini, look for the open cluster 00:14:56.320 --> 00:15:00.769 Messier 35. It's a rich, wide cluster that works 00:15:00.769 --> 00:15:03.570 beautifully in binoculars and small telescopes. 00:15:04.269 --> 00:15:06.769 It has a loose, scattered character that feels 00:15:06.769 --> 00:15:09.929 very different from tighter, more famous clusters. 00:15:10.970 --> 00:15:14.009 Lower in the southern sky, in Pupus, you'll find 00:15:14.009 --> 00:15:18.009 a trio of often overlooked open clusters, Messier 00:15:18.009 --> 00:15:23.610 46, 47, and 93. These three make a nice study 00:15:23.610 --> 00:15:27.250 in contrast. One dense and rich, another loose 00:15:27.250 --> 00:15:30.509 and brighter, and one smaller and more compact. 00:15:31.129 --> 00:15:33.549 They're excellent targets for small telescopes 00:15:33.549 --> 00:15:37.029 once they've climbed clear the horizon. For a 00:15:37.029 --> 00:15:39.370 globular cluster that tends to fly under the 00:15:39.370 --> 00:15:43.009 radar, look just below Orion toward the constellation 00:15:43.009 --> 00:15:47.970 Lepus from Messier 79. It appears as a tight 00:15:47.970 --> 00:15:51.549 concentrated glow through modest telescopes and 00:15:51.549 --> 00:15:54.009 offers a very different feel from the more famous 00:15:54.009 --> 00:15:58.129 globulars that dominate summer skies. Observers 00:15:58.129 --> 00:16:00.669 with darker skies may want to spend some time 00:16:00.669 --> 00:16:03.750 in Monoceros, the faint constellation between 00:16:03.750 --> 00:16:08.769 Orion and Gemini. Here you'll find NGC 2264, 00:16:09.350 --> 00:16:11.730 sometimes called the Christmas Tree Cluster. 00:16:12.350 --> 00:16:14.970 It's a subtle region combining a scattered group 00:16:14.970 --> 00:16:18.610 of young stars with faint surrounding nebulosity. 00:16:19.269 --> 00:16:22.230 This is not an object that jumps out immediately. 00:16:22.519 --> 00:16:26.100 It rewards lingering, careful -looking, and wide 00:16:26.100 --> 00:16:36.659 -field views. Before we go, I just wanted to 00:16:36.659 --> 00:16:40.860 note a quick milestone. February 4th marked the 00:16:40.860 --> 00:16:44.779 second anniversary of Star Trails. Last year, 00:16:44.820 --> 00:16:47.519 I did a special episode to commemorate the show's 00:16:47.519 --> 00:16:50.210 first anniversary. And in it, I talked about 00:16:50.210 --> 00:16:53.090 how the show was produced and why I started it. 00:16:53.309 --> 00:16:56.750 That was back in episode 50 on February the 2nd, 00:16:56.850 --> 00:17:00.730 2025, if you're curious. I don't have anything 00:17:00.730 --> 00:17:03.990 special planned for this anniversary. My goal 00:17:03.990 --> 00:17:07.230 is to continue cranking out episodes and refining 00:17:07.230 --> 00:17:10.069 our approach and just try to make each episode 00:17:10.069 --> 00:17:13.369 better than the last. The crazy thing is there's 00:17:13.369 --> 00:17:16.130 now nearly two years worth of astronomy content 00:17:16.130 --> 00:17:19.359 in our back catalog. That has to count for something. 00:17:20.240 --> 00:17:23.200 As always, if you have show ideas, topics, or 00:17:23.200 --> 00:17:25.779 questions, feel free to connect over at the show 00:17:25.779 --> 00:17:31.960 website. That's going to do it for this week. 00:17:32.099 --> 00:17:34.299 If you found this episode interesting, please 00:17:34.299 --> 00:17:37.019 share it with a friend who might enjoy it. The 00:17:37.019 --> 00:17:39.319 easiest way to do that is by sending folks to 00:17:39.319 --> 00:17:43.619 our website, StarTrails .Show. And, if you want 00:17:43.619 --> 00:17:45.880 to support the show, use the link on the site 00:17:45.880 --> 00:17:49.700 to buy me a coffee. That really helps. Be sure 00:17:49.700 --> 00:17:52.779 to follow Star Trails on Blue Sky and YouTube. 00:17:53.259 --> 00:17:56.119 Links are in the show notes. Until we meet again 00:17:56.119 --> 00:17:58.720 beneath the stars, clear skies everyone.