Deep Astronomy - The Triangulum Galaxy: The Most Distant Naked Eye Object

0:00It's the 365 Days of Astronomy podcast, coming in 3, 2, 1.

0:20Hello, space fans, and welcome to Your Sky Tonight. My name is Tony Darnell from deepastronomy.space. This week, after setting our clocks back an hour, and the night sky takes center stage in our early evening hours in the Northern Hemisphere, we are going to take a look at one of the most distant objects that can be seen with the naked eye, the Triangulum Galaxy.

0:51Rising in the east shortly after sunset, the constellation Triangulum appears. The constellation itself is hard to find, because it consists of only a triangle, and we can make out many of those in our connect-the-dots patterns that make up the constellations. So the easiest way to find Triangulum is to look for the great square in the constellation Pegasus.

1:21I know, finding a square is also really easy to do, and there appear to be many of those as well. But this one is very bright, and sits relatively close to the distinctive constellation of Cassiopeia. So, after locating the great square of Pegasus, follow it down toward the horizon and past Andromeda. And if you are out on a very dark night, you'll also see the Andromeda Galaxy in between Cassiopeia and Andromeda.

1:53The constellation Triangulum itself is an unremarkable, dim triangle, but it is home to a remarkable object, the Triangulum Galaxy, or M33. This galaxy is actually visible to the naked eye on very dark nights. Like the Andromeda Galaxy, it appears as a faint smudge that is best viewed using your peripheral vision. That's the part of your eye that is most sensitive to very dim, grayscale things.

2:27The galaxy appears between the triangle and the bright star in Andromeda called Mirac, and you may have noticed its close proximity in the sky to the Andromeda Galaxy. That's because the Triangulum Galaxy is a member of our local group of galaxies that include Andromeda and the Milky Way. In fact, the Triangulum Galaxy is the third largest in our local group, and many astronomers think it is gravitationally bound to Andromeda.

3:05It is a little farther away from us than the Andromeda Galaxy. The Triangulum is approximately 3 million light-years from us, while Andromeda is only 2.5 million light-years away. Here is an image of M33 taken with amateur equipment. And here is one taken from the Very Large Telescope in South America, which shows glowing red gas in the spiral arms.

3:35This galaxy is 60,000 light-years across, and contains some 40 billion stars. By comparison, our galaxy, the Milky Way, is home to over 400 billion stars.

3:51If the Triangulum Galaxy is in fact linked with Andromeda, as many astronomers believe, then we can expect this galaxy to also take part in an amazing galactic collision in a little over 2.5 billion years between the Andromeda Galaxy, the Triangulum Galaxy, and our own Milky Way Galaxy. When this occurs, all three will be torn apart by gravitational tidal forces,

4:21and will gradually reform into a larger galaxy, perhaps producing one of the largest in the universe, a mighty elliptical. So go outside tonight on this crisp fall evening and look toward the east early in the evening and try to find this nondescript triangular constellation called Triangulum. Well, that's it for now, space fans. Thank you all for listening. And as always, keep looking up.

4:55You are listening to the 365 Days of Astronomy podcast. The 365 Days of Astronomy podcast is produced by the Planetary Science Institute. Audio post-production is by me, Richard Drumm. Project management is by Aviva Yamani.

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5:56we won't be able to share the stories and inspire the worlds. We invite you to join our community of storytellers and share your voice with the listeners worldwide. As we wrap up today's episode, we're looking forward to unraveling more stories from the universe. With every new discovery from ground-based and space-based observatories and each milestone in space exploration, we come closer to understanding the cosmos and our place within it. Until next time,

6:27let the stars guide your curiosity. Society G

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