M11 - Wild Duck Cluster - Deep Sky Videos
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- Опубликовано: 3 дек 2024
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Variable "Delta Scuti" stars are a big part of our chat about Messier 11, an open cluster named after wild ducks.
Discussed by Professor Michael Merrifield from the University of Nottingham.
The paper being discussed is at: bit.ly/1pRgVnU
With thanks also to Richard Townsend, ESO and our usual band of astro imagers.
Tiny bit of extra footage from this interview: • Delta Scuti Stars (ext...
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Video by Brady Haran
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So glad you decided to keep putting out the Deep Sky videos! Thank you Brady!
We enjoy doing them - thanks for watching.
I thought I knew pretty much everything about variable stars back in 1980 when I got old enough to read more into-depth astronomy books, but I never heard about opacity-based variations, especially within one single star. It's an amazing finding.
Those opacity-based stars are of crucial importance for cosmology since they are integral part of the cosmic distance ladder. And if you watched last episode of "Cosmos": It was "Pickering's Harem" who discovered and systematically analyzed them.
this cluster is a gem in my 4" refractor. triangular on direct vision and circular with averted vision.
I really appreciate the amount of work you've put into making these videos. I'm binge-watching the entire series - so interesting and educational!
This is a beautiful cluster in a small telescope!!!
I found this fascinating. Particularly the idea that light takes 'thousands of years' to escape from a star. And I think Brady and Prof Mike make a great team for getting this kind of idea across - thanks guys. No comments so far - I guess Brady hasn't processed them yet.
One more fantastic video ! Thank you for sharing this knowledge.
you're welcome
Fascinating and very clearly explained. Cheers, Brady.
Thank you so much, these videos are awesome!
That was a really great video Brady. Hope to see more videos like this!
There is an outlier in the bottom right that neither of them mentioned. Outliers are often more interesting.
An other excellent one in the sequence. Thank you
These videos are genius! Both literally and figuratively.
Nicely done. Note that the kappa-mechanism mentioned in the video is responsible for the existence of a star type that has been very important to establish cosmic distances, and which were discovered and extensively analyzed by "Pickerings Harem" mentioned in the latest episode of "Cosmos".
Any explanation for the Delta Scuti star with Temp ~1.7, far outside the swathe?
Craig Jones Probably just a field variable which was within the field that they were observing but not actually part of M11, so much farther away. That color magnitude diagram was made with apparent magnitudes, so any star that is farther or closer than m11 will look completely out of place.
Great🦆 giving in a vision: 21/July/2020. Today is 22/July/22/2020. Thank you for the information.
DeepSkyVideos Nice video :) What happened to the audio though? It seems that it's clipping a bit. Or is that just me?
Nice. I'm gonna buy an 8" Skywatcher Dobsonian soon, hopefully I'll be able to see a few of these clusters
Make sure you acquire a good selection of eyepieces to go along with it - clusters are beautiful both as a whole, and viewed up close - don't want to miss either views :)
I had an 8" and pretty much as soon as I bought it I wished I had bought a 10 or 12" with a goto mount / tracking mount.. I had plenty of eye pieces though.
I ended up buying the 10" Skywatcher FlexTube (no goto). It came with a 25mm & 10mm eyepieces, and I bought a 4mm eyepiece to go along with it. So far I'm enjoying it immensely :)
It would be cool if you could do a video on variable stars. I did my final year project on cataclysmic variables and they are pretty interesting systems.
sir does photons have mass ?? , if they don't , then why is there radiation pressure ?? , and why is does photons have momentum(p=mv) ??
sir please answer this question . It will help me a lot .
What about the Andre' Cold Duck cluster?
How does the ionization of the element Helium make the star more opaque?
Never mind, to my understanding the free electrons that were "ripped off" interact with the light more. Thus, resulting in a more opaque star.
An unrelated suggestion for a video is what if a star randomly was introduced into the solar system a certain distance away. It popped into existence if you will. At what speed will the gravitational attraction from this star be felt? Will the force be felt at the same time the light from it reaches us; the speed of light? Slower and if so by how much? Is there a way to detect the speed of gravity today?
zazobege That's actually a fairly old problem and is closely related to general relativity. Only the problem was, "If the sun spontaneously disappears, when will the Earth leave orbit?" One theory is that it will cause a massive gravitational wave that will push Earth away and that this wave travels at the speed of light. Another theory is that space can move as fast as it wants, because it's not a particle, it can travel faster than light. (Which means that the universe could expand faster than light). Google it.
There's actually a Vsauce video on this. v=rltpH6ck2Kc
The short answer is that the speed of light is also the speed of gravity.
The empirical observation of gravitational waves finally also further confirmed what we earlier thought: the speed of gravity is indeed the same as the speed of light. It's pretty much the "speed of causality."
Hey Braddy, you videos coud have a more louder sound. All you channels have an audio that is too low to hean in comparission with other videos on you tube.
There's something else I've learned. Thank you.
But is his shirt black and blue or white and gold???
Did that star have a rotating icosahedral shape?
Fantastic video, very interesting :)
gnarf... everytime they showed the graph, I hoped they's mention - and explain - the outlier. but they didn't. can somebody explain? ;)
Which outlier are you referring to? Above HV7 or the * on the lower right?
Why is it called opacity instead of the star's "refractive index"?
I think the refractive index concerns more the speed by which the light travels through a medium, where as opacity concerns the lights capability to travels through the medium.
fascinating stuff. thanks for those awesome videos.
Idea for another video: What would happen if we could extinguish a star? What would become of it? Would it clump together into a giant lump of mass? Would it spontaneously reignite itself? What effect does the size of the star being extinguished have on the result?
I think VSauce did a video about this or mentioned it in a video
thanks...are these akin to Cephid variables??
Cepheids are also unstable through the kappa mechanism, so live in the unstable swathe that cuts through the colour-magnitude diagram, but they live higher up, as they are bright giant stars nearer the end of their lifetimes, while the delta scuti stars are main sequence stars in the earlier phase of their lives.
Michael Merrifield
Thanks Michael
Perhaps you could talk about Henrietta Swan Levitt's painstaking analysis of the photos taken that gave the clue to this variability in these stars?
They ARE Cepheid stars. "Dwarf Cepheid" is another name for a "delta scuti".
EDIT: I love the fact that you reply to comments, Dr. Merrifield!
well I love the fact that you post such interesting things...and I love the off camera questioning so thank you for taking the effort.
I showed your posting to my astronomy friends here in Melbourne.
they took great interest in your work.
what is Chile like??
is this what he mentioned in the GoT video?
6:04 Thousands of years for light to escape its star. Interesting to know. I'm pretty sure I'm glad that our is not delta scuti.
+aMulliganStew Light takes thousands of years to exit our sun too!
Cluster duck.
lol stupid request here..
could we get a professional opinion of Nibiru.
also the increasing occurrences of near earth objects being mentioned and exploding in our atmosphere? (the rock that blew up over Siberia and the most recent "the beast")
5:57 - the light takes a long time to get out of a star? Okay. EVERYTHING I thought I knew about stars = in the bin.
It's the time from the core to the surface that is about 170,000 years due to the amount of matter the photons have to get through. They mostly just bounce around inside until the eventually reach the edge, then take 8 minutes to get to our eyes...
Here, have a read at this.
sunearthday.nasa.gov/2007/locations/ttt_sunlight.php
The sun (stars by association) are amazing things.
The speed of light is about 300 million meters per second... IN A VACUUM.
If it's going through matter (gas, liquid, solid, or plasma) it bounces around, so we say it goes slower.
The plasma in a star gets very VERY dense as you go down towards the core, so light goes slower and slower.
What's up with that Delta Scuti at about [1.6, 17.5] in the diagram? A hipster Scuti? :D
Thanks again
Why do these videos not show up in my subscriptions even when I'm subscribed?
What would life on Earth be like if our sun were replaced with one of these variable "Delta Scuti" stars - one that was of comparable size to the sun?
If light produced within the sun takes thousands of years to escape the star, does that mean that the light we sun from our sun is thousands of years old already?
"Delta squishy stars". Every time. No one else heard this? I mean it kind of fits, they change their density in a way. Measured by their 🔺sqy?
So the K mechanics is why sun spot are hotter than the rest of the sun
What's with his skin?
Solar imaging would be fun living in a contact binary star system. :)
interesting
Quack
Gorilla scientists call it the Wild Gorilla Cluster
I would like to know what would happen to the Earth if our sun did the wibbly wobbly bit. Somebody spill the beans!
Duncan Gunn The Sun's brightness would be varying considerably, causing the weather on Earth to vary much more than it does now. Would be my guess at least.
No body pointed out in all these years that the prof is wearing a White and Gold T-shirt? ;)
blue and gold(brown)
Since when is blue hot and red cold....
its the energy-level of the photons. blue light carries more energy per photon than red light does. and if you heat something to extreme temperatures, as temperature rises, it will get red, then orange, then white, then blue, then you get more and more UV light, and finally x-rays.
kurtilein3 please check your facts before answering such questions.
light is an electromagnetic wave and has a wavelength and the shorter it is the more energy the individual photon (light particle) has.
The color that you see is also dependent on the wavelength of the photon (red 700 nm to violet 400 nm) and are distributed like this upload.wikimedia.org/wikipedia/commons/f/f1/EM_spectrum.svg
and then there are a few colors that are a combination of different colors and white light is just all of the visible light at once
spinnenente
my facts are fine. the energy level and the wavelength can be used interchangeably. the amount of energy is equal to a known constant divided by the wavelength.
and when you heat an object, like a piece of platinum in a high temperature flame, or look at stars of different surface temperatures, you will never see green. never ever. there is a graphic in the wikipedia article called "black body radiation" , its the second one, it shows the appearance of black body radiation to human perception in a mathematically defined color space. its the black line. you see that the black line goes through red, orange, white, and blueish white.
so i dont see a problem with my comment. it fits observation, and the mathematics and models. i dont see anything wrong with my facts.
spinnenente
kurtilein3 's explanation holds, and does not conflict with your contribution. He's describing black-body radiation, while you're examining it from a quantum perspective.
spinnenente; You seem to be saying the same thing as kurtilein3 is. 400 nm ("blue") is a shorter wavelength, and thus a higher frequency, then 700 nm ("red").
Is nuclear fusion in the core a proven fact, or is it still a theory?
+tomahawkskipper its proven as far as anything can ever be proven with certainty. Knowing about the fusion processes inside stars is the very basis for 99% of modern deep space astronomy. Plus Fusion has also already been achieved a lot of times in labs around the world - it is highly unlikely that any other mechanism could explain all the different observations we make every day
+tomahawkskipper Hydrogen bombs use a fusion process.
"The light can take thousands of years to escape" - ?
Is that an exaggeration?
Imagine this - when a photon is created, think of a pea being 'born' at the bottom of a huge bubbling cauldron of extremely thick pea soup (the soup being plasma?), so there you have your new little pea - jostling around with a trillion other peas, just waiting for it's chance to finally break on through to the surface. ok - now, I'm hungry...
Most importantly, the photon that is created in the core is not the same photon that leaves the surface as 'light'. That photon gets absorbed by the first Hydrogen atom that it hits. When that atom smashes into another atom then another photon is emitted - and so on. This is called the proton-proton chain and is the reason why it can take so long to get out of the core (if at all).
Don't think that the photon created in the core just knows how to make a bee-line for the star's surface. It doesn't know. The 'randon walk' as it is sometimes called is a result of the proton-proton chain.
wooter
not first