A real shooting star - Mira leaves a 13 light-year tail
tags:
Stumble ThisMira is a true shooting star, i.e., an actual star moving so fast relative to its neighbors that it leaves a nebulous tail 13 light years long. Watch and learn.
X Greetings! You are not currently logged in, but please don't let that stop you from voting up any videos you like. :)
|
| |||||||||||||||
mira,shooting,star,ultraviolet,tail,spitzer,galaxy,evolution,explorer A real shooting star - Mira leaves a 13 light-year tail
Comments  playlists with this video Nature, science, geek, and how to by kronosposeidon
who voted for this video kronosposeidon
- Gratefulmom
- siftbot
x34 - ant
who has this post bookmarked Constitutional_Patriot
- youmakekittymad
A Real Shooting Star - Mira Leaves A 13 Light-year Tail Related Videos
| Watch this Video NextFriends O' the Sift Top New Videos by Vote  Subscribe Top 15 Sifters of All Time Top 15 Sifters of the Past Week 8. lore_weaver
(225 votes) Newest Appreciated Comments        | ||||||||||||||
Actually, I just did some rough calculations, and at roughly 64 km/s, that would mean it's been glowing for more like 60k years? Is its velocity that variable?
I'm pretty confident it's not releasing energy on the scale of a supernova. Material from a supernova is ejected at much higher velocities (orders of magnitude greater). And doesn't the remaining neutron star or black hole continue to provide energy to the surrounding shell?
In the case of a supernova remnant, there is an expanding shell of (a vastly greater amount of) matter that continues to slam into the surrounding material. When a supernova first blows up it can outshine the galaxy it's in. The expanding shell of material continues to sweep up more matter and the whole system grows much dimmer very quickly. Also, a supernova remnant (usually?/always?) has a continuing source of energy from whatever is left over at the center.
As I wrote to KP, I'm definitely not an astrophysicist - just trying to wrap my head around this really weird phenomenon.
angular velocity=velocity/radius
Also, my guess is: You are trying to backwards calculate the energy. You have to use the reletavistic correction for something going this fast.
I have to pick up some business cards and go to the gym. I will reply more in a couple hours.
>> ^jonny:
re: velocity - The 64km/s (≈ 143000mph) is radial velocity, so I guess it's not relevant, but I can't find any reference to its linear(?) velocity...
http://en.wikipedia.org/wiki/Mira
The simple answer is that it is a star.
Stars, like ours, emit radiation as a result of nuclear fusion. As it moves through space, the radiation creates a bow, where that radiation interacts with hydrogen. My guess is the hydrogen is excited to a higher energy state. When it decays, it emits the ultraviolet light that is whipped around the star in the shape of a tail.
You can't treat Mira with the same math and logic as a comet, because it produces its own energy.
You can't treat Mira with the same math and logic as a comet, because it produces its own energy.
I wasn't thinking of it like a comet, which does not emit energy (does it?). A comet's tail is created from material being stripped away by solar wind, and is visible because of reflected sunlight, correct?
The question about velocity was not a lack of understanding of basic physics, but a lack of a good description of Mira's linear velocity relative to the material through which it's passing. The wiki article only vaguely mentions it in passing, and notes its radial, not angular, velocity in the sidebar. Thanks for the nasa link, though, as that answers it exactly. It's linear velocity is roughly 130 km/sec, which translates to a distance of roughly 13 light years in 30000 years. Cool - that was the easy part.
But apparently I'm not getting my main question across very clearly. I understand that stars use fusion to generate the energy they are emitting. But the distal end of that tail is 13 light years away from the star and has been emitting UV radiation for over 30000 years. My question is not about the amount of energy released, but the rate at which it is being released. Are you suggesting that excited hydrogen atoms are taking over 30000 years to return to a low energy state without undergoing any other interaction after the star has passed?
A vast amount of energy is transferred to the interstellar hydrogen gas in a fairly short amount of time as Mira zooms by, but then the hydrogen is taking 30000 years to release that energy? That's what I'm not understanding. I mean, if hydrogen atoms can store that much energy for that long, then I'd recommend one of you smart physicist types start looking into hydrogen based batteries!
In all reality the neighboring interactions could kick the electrons back to excited states and they could decay again. You follow. So even thought it might not take that long typically for it to decay, the fact is it's neighbor has emitted exactly the right energy to excite it back up into the excited state. My guess is you can't ignore nearest neighbor interactions and think of it as a linear process.
Secondly, hydrogen was just a guess. It could be something else that takes long to decay, a hydrogen isotope. Lots of material emit radiation in the UV for astronomically long times.
Also from the pic it looks like it is traveling through something, disrupting some field or gas we cannot see. Kind of like a rock passing through water or thick smoke. If you look closely at the pic you can see some distinct rippling affects and even a spiral affect close to the tail of the star. Something is distrupting the flow of that matter. Another gravity field produced nearby perhaps? Maybe not.
So the rate of decay would be slow as the star drags along the matter keeping it hot and whatever it is passing through providing the constant fuel to maintain the burn. Over time the matter slowly decelerates, cools and fades from our vision.
All in all it is still a guess.