I love how clear these professors of the deepsky video series are able to make their subject matter... "Stars and galaxies... are the sprinkles on top of this vast sea of gas and dark matter." Lovely
I learn an awful lot from Dr. Gray. She has such a nice way of dumbing down the material enough to be understandable, but not to the point of feeling like you are being talked 'down' to. It's obvious she enjoys her work, and I enjoy watching her enjoy her work :) Aloha nui and mahalo!
I love how the astronomers always want to be like "duh Brady" when he says something like "M90... just wondered on into this gang" as if we haven't covered galactic bodies growing through merging many, many times before. Mad respect to Dr Meghan Gray for keeping her cool when Brady goes to his "i don't really know much about things lens". (,which is obviously for the viewers benefit, and I appreciate it a lot, thank you Brady). And thank you to the astronomers for doing such a magnificent (lol) job teaching us. Lots of love to the whole team (sheepishly I think I am in love with Dr. Becky, wow I wish I could meet her sometime and just have a conversation)
All of my favorite Sixty Symbols heroes have their specific video where they truly show their mastery of the field. I think I just found my DeepSky heroine.
Something that seemed to be "assumed" in the video, but never explicitly stated (or I just missed it). So are all of these Messier objects part of one actual cluster (cluster of galaxies, it would appear, if that is really the case), or do they just appear to be close from our vantage point? Once again, I could have missed it early on.
No, they are not. All non galaxy Messier objects are in our own galaxy the Milkyway or its halo. Together with the Milkiway the galaxies M31 Andromeda Galaxy and its two satellite galaxies M32 and M110, and M33 Triangulum Galaxy. The Virgo Galaxy Cluster contains the 16 Messier galaxies M49, M58-M61, M65-M66, M84-M91, M98-M100. Both these galaxy cluster are part of the Virgo Supercluster together with the clusters/groups Canes Venatici I Group (M94 & M106), Virgo II Groups (M61 & M104), Leo I Group (M95, M96 & M105), M51 Group i Canes Venatici (M51 & M63), Ursa Major Cluster (M109 & maybe M108), M74 Group (M74), M81 Group (M81& M82), Centaurus A/M83 Group (M83), M101 Group (M101), NGC 5866 Group (M102 = NGC 5866) and NGC 1068 (M77=NGC 1068). M64 is with 60% certainty a part of the Virgo Cluster and if not it is each own group which also is a part of the Virgo Supercluster.
"Stars and galaxies, they're just little floaty bits. They're the sprinkles on top of this vast sea of gas and dark matter." - How incredibly and wonderfully small that makes you feel, doesn't it.
What would be the interactive force being applied to the gas to strip it from M90. Is it gravitational or electric / magnetic as Dr Gray says in the end. Can we even know ? Edit: On second thoughts, if the distances involved are big, then gravitational forces should have the stronger effect, but if the distances are smaller then that might not be the case.
Is there any way to get papers like the one from the Messier 90, but for the rest of the Messier objects, explaining what´s going on thoroughly? Thanks
In this wikipedia entry, you have the list of all messier objects and a link to the detailed pages for each of them. In these detailed papers you have quite a lot of info and references to papers. en.wikipedia.org/wiki/List_of_Messier_objects
Yes. Although they're much weaker than planetary magnetic fields, they provide the transport of angular momentum required for the collapse of gas clouds and hence the formation of new stars.
calling something that huge "weaker" than something as small by comparison as the earth misses the point entirely "Gauss" is only ONE aspect of a quantum field. the amount of total power represented by the two fields cant even be compared.
As far as I understand a jellyfish galaxy has starburst along the trailing gas. But M90 has no starburst in its trailing gas. With the red trailing gas it could be called the Lion's Mane Jellyfish Galaxy.
Yes. Intergalactic gas has a density of about one atom per cubic meter. Interstellar gas is about one atom per cubic centimeter. Our atmosphere has billions of atoms per cubic centimeter.
FTLNewsFeed - Nonononono, that's the energy density, not the mass. Shame on you. About 15% of the mass is normal matter, and 1,5% is in stars. You're talking about energy density, which includes dark energy. Better luck next time
Can someone explain the role of dark matter in a single galaxy? I remember reading something about how galaxy formation only makes mathematical sense when dark matter is included, but does that mean without dark matter the galaxy would collapse, or spin apart? Or am I entirely misinformed?
May or may not be the answer to your question but watch their video on the whirlpool galaxy. Dark matter isn't mentioned in the video but it could definitely help you understand how spiral galaxies get their shape.
The outside of the galaxies are moving way faster than they would if only the visible matter were there. Like how Neptune takes forever to orbit the sun while Mercury takes hardly any time at all -- that doesn't happen in galaxies. The outside goes at a much more similar rate to more inside stars so if the galaxy were like our solar system, at such speeds they wouldn't be gravitationally bound and would fly off. So there must be more mass in the galaxy system for the speeds to be accurate based on gravity equations.
Ohhh, thanks! Oh wait, then how come galaxies are both gravitationally attracting each other, AND expanding apart? Is it just a matter of distance, like how Andromeda and the Milky Way are colliding but more distant galaxies are retreating? I guess I'm really asking, does dark matter only really effect the universe on the galaxy scale, but not bigger or smaller than that?
Some galaxies are close enough to be gravitationally bound so will be pulled toward each other (perhaps on this scale dark matter plays a role -- I don't know enough to say). Other galaxies are not bound to each other (or are part of a galaxy group which is not bound to a different galaxy group) and will recede from each other due to the expansion of spacetime from dark energy (a different thing from dark matter). It's entirely reasonable to extrapolate that on our earth/human/cellular/etc scale, dark energy plays a role, but the things here are so tightly bound by gravity and the electromagnetic force, and the scales of expansion itself are so small that it might as well be ignored.
-Whenever you notice something like these weird galactic structures, a magnetic field did it. -I see, alright, yes, but in this galaxy... -Magnetic field!
why would they still be debating how things like star clusters start/stop when we have incredible supercomputers? Surely you could simulate a galaxy now? At least on a star level.
I read somewhere that if you removed all the space between the atoms, all of humanity could be compressed into something the size of a pebble. Though it would still have the same mass as the combined mass of humanity. If we did this to ALL the matter in the universe, how big an object would we make? Exactly how much matter does the universe contain if visualized in a solid lump.
Yep, and gravity is a choc top, binding the hydrogen together into a roughly spherical collection of atoms. Sometimes you get star formation, which is sprinkles. The flake is just a flake, it doesn't mean anything.
en.m.wikipedia.org/wiki/Interstellar_medium I had the same question - and I googeled it :-). There's always some questions coming up with these videos - so they make me look up stuff and learn new things.
"Action packed C.B.D, boring suburbs." CBD = Central Business District, for my fellow Americans. I only know this because I visited Sydney and Melbourne for the first time 6 months ago.
I wonder where Meghan is from. Her accent sounds basically American, but there are a lot of features that don't fit. I guess she's spent a long time in England?
Deep Sky videos! Interesting Astronomy lady! Over 9 minutes! Thanketh Oh greateth Bradyeth. Ram pressure stripping! Oh my god mister Haran, that is the absolute best term I've learned from your videos for so many reasons.
What is the density of this H gas? It's hard to imagine it at millions of Kelvins if the density is like high orbit of Earth... How would the molecules bump on each other to have this temperature?
Temperature is a measure of how much energy the particles have. Pressure would be the measure of how much they bump into each other. For a fixed volume, increasing temperature does increase pressure, but the volume we are talking about here is so large that the pressure will still probably be quite low even at a high temperature.
Temperature is a measurement of how strongly an atom/molecule is oscillating. At absolute zero molecules are at rest & do not vibrate. The harder an atom/molecule vibrates, the more energy in contains, the higher its temperature. Pressure is also related, because an atom has to have something to vibrate up against.
trespire exactly! So how can this hydrogen have meaningful temperature if the density is as low as outer space over here? If the density is higher is would not have dissipated it self to outer space?
Rodrigo Marques Everything has a temperature. Low density hydrogen gas, located in a very low activity volume of space, will sometimes be just a few degrees above absolute zero. But if the gas is excited, by for example electromagnetic radiation from a near by star (ultra-violate, X-ray etc..) it's temperature will rise. I am no astrophysicist, but this is what I understand.
It's amusing how scientists talk about "dark matter" as if we know for sure that it exists. There is no direct evidence for dark matter. It is just a hypothetical construct to "save the theory". It will be interesting if they ever get any evidence for it. (Who ever does will undoubtably get the Nobel Prize.)
It depends on how you define "direct evidence". If you say, we have to observe it through other that gravity and we have to know what it is made of, you are right. But the indirect evidence is so overwhelming, that actually, nobody doubts the existence of dark matter anymore.
+Ronald de Rooij Nobody doubting it is what is so amusing to me. Yes, it is obvious that there is something going on that we don't understand but to call it "matter" is just an assumption with no real proof. There is something that has some of the same effects as matter but we don't know enough about it to really assume there is some physical existence of the stuff.
Hm.. So how does this one come towards us??.. Dark matter.. Dark energy.. I think we are completely off.. Also a few years ago elec. magnetism had little to no role to play.. Now it looks like its the force that is everywhere.. I believe we need to rethink what we know..
I love how clear these professors of the deepsky video series are able to make their subject matter... "Stars and galaxies... are the sprinkles on top of this vast sea of gas and dark matter." Lovely
I learn an awful lot from Dr. Gray. She has such a nice way of dumbing down the material enough to be understandable, but not to the point of feeling like you are being talked 'down' to. It's obvious she enjoys her work, and I enjoy watching her enjoy her work :) Aloha nui and mahalo!
I love how the astronomers always want to be like "duh Brady" when he says something like "M90... just wondered on into this gang" as if we haven't covered galactic bodies growing through merging many, many times before. Mad respect to Dr Meghan Gray for keeping her cool when Brady goes to his "i don't really know much about things lens". (,which is obviously for the viewers benefit, and I appreciate it a lot, thank you Brady). And thank you to the astronomers for doing such a magnificent (lol) job teaching us. Lots of love to the whole team (sheepishly I think I am in love with Dr. Becky, wow I wish I could meet her sometime and just have a conversation)
Awesome video, i like all videos where Meghan is featured.
thanks Megham! i'm glad you're looking out for all the DSV Fans!
Awesome necklace!
awesome nice work mate cheers been hanging out for a DSV
Very instructive! Fascinating subject too! Her way of explaining things is outstanding!
How dense is the gas that m90 is passing through? Is it more or less dense than the sparse interstellar gas between our sun and nearby stars?
4:39 A face I can't unsee. Stop staring at me with your galaxy eyes!
84 and 86 eyes
You speak so well and so clearly!
can you make a video for bootes void.i want to knows why its empty.
I'm curious how many light years away this is. In other words, I'm wondering how long ago this happened.
makes you rethink the idea of time ya know. since we're seeing into the past but it's our present.
All of my favorite Sixty Symbols heroes have their specific video where they truly show their mastery of the field.
I think I just found my DeepSky heroine.
What are the others?
Love the way she explains things.👌
that necklace is pretty darn cool.
Something that seemed to be "assumed" in the video, but never explicitly stated (or I just missed it). So are all of these Messier objects part of one actual cluster (cluster of galaxies, it would appear, if that is really the case), or do they just appear to be close from our vantage point?
Once again, I could have missed it early on.
Wikipedia to the rescue - yes, the Virgo cluster is an actual cluster of galaxies :)
No, they are not.
All non galaxy Messier objects are in our own galaxy the Milkyway or its halo.
Together with the Milkiway the galaxies M31 Andromeda Galaxy and its two satellite galaxies M32 and M110, and M33 Triangulum Galaxy.
The Virgo Galaxy Cluster contains the 16 Messier galaxies M49, M58-M61, M65-M66, M84-M91, M98-M100.
Both these galaxy cluster are part of the Virgo Supercluster together with the clusters/groups Canes Venatici I Group (M94 & M106), Virgo II Groups (M61 & M104), Leo I Group (M95, M96 & M105), M51 Group i Canes Venatici (M51 & M63), Ursa Major Cluster (M109 & maybe M108), M74 Group (M74), M81 Group (M81& M82), Centaurus A/M83 Group (M83), M101 Group (M101), NGC 5866 Group (M102 = NGC 5866) and NGC 1068 (M77=NGC 1068).
M64 is with 60% certainty a part of the Virgo Cluster and if not it is each own group which also is a part of the Virgo Supercluster.
always enlightening to listen to Dr. Gray speak
Are stars constantly bring fed gas pulled in by gravity from the surrounding universe and so in a way growing as well as aging and dying?
"Stars and galaxies, they're just little floaty bits. They're the sprinkles on top of this vast sea of gas and dark matter." - How incredibly and wonderfully small that makes you feel, doesn't it.
yay! meghans back!
4:39 M86 M84 face is watching you sleep at night.
Can you do an episode on dark radiation? Thanks.
Back to school for you
Hjembrent Kent
I'll take that to mean that you have never heard of dark radiation.
What would be the interactive force being applied to the gas to strip it from M90. Is it gravitational or electric / magnetic as Dr Gray says in the end. Can we even know ?
Edit: On second thoughts, if the distances involved are big, then gravitational forces should have the stronger effect, but if the distances are smaller then that might not be the case.
Is there any way to get papers like the one from the Messier 90, but for the rest of the Messier objects, explaining what´s going on thoroughly?
Thanks
In this wikipedia entry, you have the list of all messier objects and a link to the detailed pages for each of them. In these detailed papers you have quite a lot of info and references to papers. en.wikipedia.org/wiki/List_of_Messier_objects
Could M87 be grabbing at M90?
Maybe do the Caldwell catalogue after the messier?
"Must be magnetic fields" now I know why they keep showing up! :D
But how do they work?
4:40 it's a face :D
Why don't astronomers ever consider electric fields as a possible explanation for things?
How dense is the gas? Is it like an atmosphere and how does it stay so hot if space is so cold?
What does false color images mean? Thanks
Speaking of magnetic fields. Do galaxies have magnetic fields?
Yes. Although they're much weaker than planetary magnetic fields, they provide the transport of angular momentum required for the collapse of gas clouds and hence the formation of new stars.
INCBraindead Thank you
calling something that huge "weaker" than something as small by comparison as the earth misses the point entirely "Gauss" is only ONE aspect of a quantum field. the amount of total power represented by the two fields cant even be compared.
My favorite Astronomer!
Great video, that's a very interesting galaxy.
Brady, is there a patreon for deepskyvideos?
H-alpha light is the brightest hydrogen spectral line in the visible spectral range. In case you were also wondering.
As far as I understand a jellyfish galaxy has starburst along the trailing gas. But M90 has no starburst in its trailing gas.
With the red trailing gas it could be called the Lion's Mane Jellyfish Galaxy.
Still waiting on M94. It's worth your time.
more!
I thought dark matter and dark energy were what astronomers said if they didn't know what was going on.
Dr. Gray is bae.
Why is there aluminiumfoil on the wall behind her?
To protect from strange signals or be used as a hat
Picobyte she's growing pot in the next
Room
I can already tell I am going use "invoke magnetic fields" a lot when explaining things to people.
6:30 Not jellyfish. Is Spaghetti monster! :D
When you say 'gas' ... how dense is that intergalactic gas? Rather thin compared to our atmosphere I'm guessing.
Yes. Intergalactic gas has a density of about one atom per cubic meter. Interstellar gas is about one atom per cubic centimeter. Our atmosphere has billions of atoms per cubic centimeter.
What percentage of the mass of the universe is in stars?
Did a quick Google search and someone said that it's probably .5%, since all visible matter makes up 4.6% of the mass of the universe.
FTLNewsFeed - Nonononono, that's the energy density, not the mass. Shame on you. About 15% of the mass is normal matter, and 1,5% is in stars. You're talking about energy density, which includes dark energy. Better luck next time
H alpha is a way of seeing Hydrogen?
That is the most nerdy necklace I ever seen. I like it.
I might be wrong here (not a native speaker), but I think I'm noticing a slight british accent developing in Dr. Meghan's speech. Very cute.
Can someone explain the role of dark matter in a single galaxy? I remember reading something about how galaxy formation only makes mathematical sense when dark matter is included, but does that mean without dark matter the galaxy would collapse, or spin apart? Or am I entirely misinformed?
May or may not be the answer to your question but watch their video on the whirlpool galaxy. Dark matter isn't mentioned in the video but it could definitely help you understand how spiral galaxies get their shape.
The outside of the galaxies are moving way faster than they would if only the visible matter were there. Like how Neptune takes forever to orbit the sun while Mercury takes hardly any time at all -- that doesn't happen in galaxies. The outside goes at a much more similar rate to more inside stars so if the galaxy were like our solar system, at such speeds they wouldn't be gravitationally bound and would fly off. So there must be more mass in the galaxy system for the speeds to be accurate based on gravity equations.
Ohhh, thanks! Oh wait, then how come galaxies are both gravitationally attracting each other, AND expanding apart? Is it just a matter of distance, like how Andromeda and the Milky Way are colliding but more distant galaxies are retreating? I guess I'm really asking, does dark matter only really effect the universe on the galaxy scale, but not bigger or smaller than that?
Some galaxies are close enough to be gravitationally bound so will be pulled toward each other (perhaps on this scale dark matter plays a role -- I don't know enough to say). Other galaxies are not bound to each other (or are part of a galaxy group which is not bound to a different galaxy group) and will recede from each other due to the expansion of spacetime from dark energy (a different thing from dark matter).
It's entirely reasonable to extrapolate that on our earth/human/cellular/etc scale, dark energy plays a role, but the things here are so tightly bound by gravity and the electromagnetic force, and the scales of expansion itself are so small that it might as well be ignored.
I understand now, thank you.
Thanks Meghan - I didn't know Galaxies made waves!
( BTW … Toronto accent? )
"magnetic fields...which, in astronomy, is usually what you invoke if you don't know whats going on". :)
that necklace thought !
What's it of? Doppler effect or something?
I think it's the phases of the moon :)
I'm pretty sure it is an eclipse.
Must be magnetic fields.
Nice necklace
-Whenever you notice something like these weird galactic structures, a magnetic field did it.
-I see, alright, yes, but in this galaxy...
-Magnetic field!
I have this weird growth on my leg. I haven't seen my doctor, it's probably just due to magnetic fields.
why would they still be debating how things like star clusters start/stop when we have incredible supercomputers? Surely you could simulate a galaxy now? At least on a star level.
I read somewhere that if you removed all the space between the atoms, all of humanity could be compressed into something the size of a pebble. Though it would still have the same mass as the combined mass of humanity. If we did this to ALL the matter in the universe, how big an object would we make? Exactly how much matter does the universe contain if visualized in a solid lump.
"I called dips on it" haha, Meghan apparently likes to make these videos. Brady, what are you bribing them with?
Oreos
Dibs.
Dibs on Oreos...
Oreos on Dibs
Cocaine maybe
I really want to hear Dr. Gray talk about the large scale structure of the universe. That would be a treat!
To quote General Macneill, Stargate, "Magnets!"
so hydrogen is like icecream?
Yep, and gravity is a choc top, binding the hydrogen together into a roughly spherical collection of atoms. Sometimes you get star formation, which is sprinkles. The flake is just a flake, it doesn't mean anything.
Castor Quinn kek
Hi
Why is this inter galaxy gas so hot?
I was expecting that everything in universe except stars & places like Venus are cold...
en.m.wikipedia.org/wiki/Interstellar_medium
I had the same question - and I googeled it :-). There's always some questions coming up with these videos - so they make me look up stuff and learn new things.
from spiral to lenticular
2.5 million light years outside of our Galaxy! Can you imagine that distance? Well if you are honest No!!
is dark matter causing any drag on the galaxy?
8008
Galaxies snowballing through the Universe!
I like the necklace :)
Hey, eyes up here buddy!
She sounds more and more British every time. Her accent is changing.
"Action packed C.B.D, boring suburbs."
CBD = Central Business District, for my fellow Americans.
I only know this because I visited Sydney and Melbourne for the first time 6 months ago.
Tracy Reed some cities call it that in the US but is usually “downtown”.
I wonder where Meghan is from. Her accent sounds basically American, but there are a lot of features that don't fit. I guess she's spent a long time in England?
She's Canadian
Is there a video that explains "hot gas" as used in this context?
Ok ram presure striping is sound like a adult movie name.
Deep Sky videos! Interesting Astronomy lady! Over 9 minutes!
Thanketh Oh greateth Bradyeth.
Ram pressure stripping! Oh my god mister Haran, that is the absolute best term I've learned from your videos for so many reasons.
Since the timescale for the Galaxy is enormous, how the aliens can be saved? 😄
The beautiful thing about video is there is no need to maintain eye discipline.
So beautiful. The galaxy too. :)
What is the density of this H gas? It's hard to imagine it at millions of Kelvins if the density is like high orbit of Earth... How would the molecules bump on each other to have this temperature?
That would mean that it's super energetic...
Temperature is a measure of how much energy the particles have. Pressure would be the measure of how much they bump into each other. For a fixed volume, increasing temperature does increase pressure, but the volume we are talking about here is so large that the pressure will still probably be quite low even at a high temperature.
Temperature is a measurement of how strongly an atom/molecule is oscillating. At absolute zero molecules are at rest & do not vibrate. The harder an atom/molecule vibrates, the more energy in contains, the higher its temperature.
Pressure is also related, because an atom has to have something to vibrate up against.
trespire exactly! So how can this hydrogen have meaningful temperature if the density is as low as outer space over here? If the density is higher is would not have dissipated it self to outer space?
Rodrigo Marques
Everything has a temperature.
Low density hydrogen gas, located in a very low activity volume of space, will sometimes be just a few degrees above absolute zero. But if the gas is excited, by for example electromagnetic radiation from a near by star (ultra-violate, X-ray etc..) it's temperature will rise.
I am no astrophysicist, but this is what I understand.
3:06
YEuh gurl, external forces all day, tell me about maagntic fields too.
this videos got potential well. VERY well
Couldn't make it first here Brady! Sorry!
Dr. Gray is so beautiful
Now I notice ... a nice chain for geeks =)
It's amusing how scientists talk about "dark matter" as if we know for sure that it exists. There is no direct evidence for dark matter. It is just a hypothetical construct to "save the theory". It will be interesting if they ever get any evidence for it. (Who ever does will undoubtably get the Nobel Prize.)
It depends on how you define "direct evidence". If you say, we have to observe it through other that gravity and we have to know what it is made of, you are right. But the indirect evidence is so overwhelming, that actually, nobody doubts the existence of dark matter anymore.
+Ronald de Rooij
Nobody doubting it is what is so amusing to me. Yes, it is obvious that there is something going on that we don't understand but to call it "matter" is just an assumption with no real proof. There is something that has some of the same effects as matter but we don't know enough about it to really assume there is some physical existence of the stuff.
Action packed CBD, boring Suburbs 😂
am i the only one who is super attracted to dr gray?
Zoidberg the milf hunter kid
wow mom what a scientific explanation.
M 90 the couch potato of galaxies.
I love intelligent women! :-*
Hm.. So how does this one come towards us??.. Dark matter.. Dark energy.. I think we are completely off.. Also a few years ago elec. magnetism had little to no role to play.. Now it looks like its the force that is everywhere.. I believe we need to rethink what we know..
My sapiosexual senses are tingleing.
I really would like them to stop talking of Dark Matter as fact, it is not!!!!
Dark matter currently is the most likely explanation for it though.
It's just lingo for "We don't really know". No need to get excited.