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AstroCatronaut t1_izh9i6f wrote

I think we are looking into the inside of the galaxy as we are on the outskirts? Also I don’t think we really know what MW looks like.

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TSCCaillou t1_izh9wzg wrote

My best guess is by taking the photos around us and constructing a diagram based on distance away.

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radlandsnatlpark t1_izhaf2f wrote

We don't have photos of the Milky Way as a whole, but all the stars you see around you are part of the Milky Way. Astronomers study the stars and build models to approximate their positions which helps give us a rough idea of what the Milky Way looks like, although there are parts we can't see very well (anything on the other side of the galactic core is mostly obscured by dust around the core itself, for example).

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Tictank t1_izhawzk wrote

If you find a 360° starmap and unwrap it flat you can generally see it's form

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MeNamIzGraephen t1_izhbj3f wrote

It's like not having a mirror, but being able to feel your face. We're "feeling" the stars with telescopes and can model of what we see based on our observations.

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Blue_Sail t1_izhbqia wrote

Do you mean something like those posters with a "You are here" arrow? That's not our galaxy.

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Cohiba_Robusto t1_izhby0o wrote

I think by mapping the stars we can see (distance, location, speed), we get a partial shape. We can then compare that known shape with other galaxies we can see, and extrapolate that we must be in the arm of a spiral galaxy. I would bet that our known data points and math are exact enough that we have a rather detailed and accurate idea of what our galaxy looks like.

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Intelligent_idiot-_- t1_izhc401 wrote

We assume our galaxy looks like most and we can tell how far are the stars around us, this allows us to have a rough approximation of our galaxy

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PoppersOfCorn t1_izhc9q9 wrote

Replying to [deleted] (#890,634)

We can see other galaxies, that's how there are photos of them. As for the Milky Way, we can see towards the centre and some of the arms so we can deduce the shape based on that and what we see from other galaxies

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PhilosophusFuturum t1_izhe7et wrote

In short; we don’t. Recent studies suggest that the Milky Way has a wobble on the edges of its outer arms like a warped record, and that it may even be bigger than the Andromeda galaxy. Also, we can map out the stars to get a pretty good idea. Other than that, we really don’t know.

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ChrisARippel t1_izheppd wrote

Before we had airplanes and satellites, people went around measuring the distances between objects on the land. Map makers took these measurements and made maps on the Earth's surface.

For the past hundred years, astronomers have been measuring the distances to groups of stars and their directions. Astronomers have used these measurements to make illustrations of the general shape of the Milky Way.

Is it perfect? No, astronomers are still discovering features of the Milky Way, such as the wave in the disc.

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ObviousGazelle t1_izhf43r wrote

All I know is on a clear moonless night 1000 miles into the sea, the Milky Way casts a shadow at your feet it's so bright. Seeing that for the first time as a grown adult, realizing the 99% of humans that came before me knew this as commonplace while it astonishes us. That's sad.

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ArtMartinezArtist t1_izhhzci wrote

We’re in it and we can plot the stars that we see all around us. Like a 3D model.

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IXICIXI t1_izhiqli wrote

How does the Milky Way compare to other galaxies? Is it the standard shape, structure and size, or is it unusual in some way?

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america4tw t1_izhjltq wrote

This made me think. How far up perpendicular to galactic plane would we need to go to get a good 'selfie'? Possible with the tech we have in a reasonable timeframe (as in several decades)?

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Psychological_Age194 t1_izhm07b wrote

Mostly through comparing other spiral galaxies to our own, applying our knowledge of stars’ locations, and constructing models from that. Our mapping of our galaxy is still in developing stages, much like maps of the world from the medieval era.

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realcuckau t1_izhmac4 wrote

I habve seen some fantastic images of the Milly way and many on youtube videos so I know what it looks like

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ramriot t1_izhmn8f wrote

Well apart from mapping the stellar distributions locally to get an idea of depth & feature of nearby arms the key way to get an overall idea if our galaxies shape is via radio observations if the neutral hydrogen emission line.

This emission line from hydrogen at a wavelength if 21cm can be plotted across the sky with variances in the frequency denoting relative velocity. combining this with models of the orbital velocity of matter in our galaxies helps in ascribing the emission to actual hydrogen clouds across the galaxy & thus builds up an overall map of matter distribution.

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its-octopeople t1_izhmrlf wrote

Replying to IXICIXI (#891,052)

IIRC, the local supermassive black hole is smaller than you'd typically get in a galaxy of our size. That also might not be a coincidence - bigger & more active black holes may be troublesome for the formation of life.

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BrotherGreed t1_izhnwoe wrote

Replying to america4tw (#891,090)

>Possible with the tech we have in a reasonable timeframe (as in several decades)?

Doubtful. I read recently that with current technology it would take us something like 18,000 years to reach Alpha Centauri, the next nearest star system. The galaxy is much, much thicker than that distance.

So unless there's some massive breakthrough on the level of sci-fi warp drives in our lifetime, I wouldn't expect any galactic selfies.

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MogLoop t1_izho5pq wrote

We don't just use visible light, you can see through the gas using different wavelengths

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jamjamason t1_izhqpbb wrote

Imagine being stuck in the edge of a frisbee. What would your view of the world look like? We can guess at the shape of the milky way because we can see that the density of stars around us is concentrated in a disc shape. And as ground based and space based telescopes get better, we get better at measuring the density of stars in different directions and distances, which improves our understanding of the shape of our galaxy.

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RealityCrash_exe t1_izhwfxt wrote

Look up the Sloan digital sky survey. Its work is INCREDIBLE. Also, thanks to such surveys, we know the distances of the stars and whether they're interacting gravitationally, as in following the same orbit around the galactic center, comparing their distance to much closer stars we know are in the galaxy with 100% certainty etc. By measuring the position, trajectories and so on, we can accurately determine its shape. On the Sloan survey website you can load up the 3d map and go fly through the universe, everything you see is exactly how it is out there in the universe

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RealityCrash_exe t1_izhxoz2 wrote

Replying to Psychological_Age194 (#891,190)

Our maps of not just the milky way, but the observable universe are far beyond any comparison to medieval era maps which in some cases were quite inaccurate. One such map we've made for the observable universe is the Sloan digital sky survey. Its one of the most detailed maps in human history, and we have a 3d model of the universe. Google it and go to its website. You can fly around the universe there in amazing detail. The amount of data it has is insane. It's literally the largest 3d map ever created

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RealityCrash_exe t1_izhyeye wrote

Replying to Psychological_Age194 (#891,613)

Sweet man. I'm sure your prof would give you extra credit if you went on sloans site and wrote a report haha I took a bunch of astronomy classes when I was in school and loved it. I went for aerospace engineering and ended up doing a minor in physics because I got obsessed with it lol Outside of that, 6 of my required electives were astronomy. 4 with the same prof who was probably the best teacher I ever had. He worked at nasa for like 16 years I think, retired and started teaching. His level of passion showed every single class. He's a rare breed.

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Bipogram t1_izhyvtd wrote

You're standing in a sparse crowd of people - you can see many people, and know their positions and speeds with respect to you quite well.

Now, those folk are stars and gas clouds - does that make it seem less mysterious that you can map their position from another vantage point?

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RealityCrash_exe t1_izhyza9 wrote

Replying to Psychological_Age194 (#891,613)

Whenever you guys discuss cosmic rays etc, if a report/project etc is asked for, if you want to blow your prof away, make an at home particle detector and take it to class for a demo. It's incredibly easy. Theres a setup called a cloud chamber. You'll be able to visibly see alpha particles etc. My prof loved it and the rest of the class was in awe.

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Accomplished-Cry7129 t1_izi0ghk wrote

Somneone had an extreme out of body experience and reported back to NASA with the details

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SpartanJack17 t1_izi199x wrote

Hello u/Riceeatingcommunist, your submission "How do we know what the milky way looks like?" has been removed from r/space because:

  • Such questions should be asked in the "All space questions" thread stickied at the top of the sub.

Please read the rules in the sidebar and check r/space for duplicate submissions before posting. If you have any questions about this removal please message the r/space moderators. Thank you.

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IXICIXI t1_izkojti wrote

Replying to everybodys_nose (#891,221)

You’re quite right. Thank you. I thought OP was suggesting that at a certain time of year (at night) we would be facing a particular direction relative to the Milky Way. So I wonder which time of year that is? Assuming this to be true for large swathes of time due to our long orbit around the centre of the galaxy…

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