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The Heliotail
July 11, 2013 5:09 PM   Subscribe

Our Solar System Has a Tail Shaped Like a Four-Leaf Clover: New Findings from IBEX.
posted by homunculus (10 comments total) 12 users marked this as a favorite

 
Totally want to learn surfing now. Also, need to come up with a way to live millennia.

My first thought on watching this: We have people that study these kinds of things? My second thought: How does this benefit mankind?

i'm just surprised at the first part. I am a knowledge for knowledge's sake kind of guy, so I am actually interested in my second question.

Also, cool!
posted by cjorgensen at 5:56 PM on July 11, 2013


This could be the missing piece in the puzzle, explaining why astrology has always been so imprecise - they hadn't factored in the good luck effect of this newly discovered astrological body.
posted by UbuRoivas at 5:58 PM on July 11, 2013 [1 favorite]


I love how much information we're able to gather from our one, limited, vantage point.
posted by jiawen at 6:02 PM on July 11, 2013 [3 favorites]


How does this benefit mankind?

the luck of the irish benefits everyone
posted by pyramid termite at 7:18 PM on July 11, 2013 [1 favorite]


Why is there a magnetic field in interstellar space? And WTF is so massive that is generating it? Super massive black hole at the center of the galaxy?

And, yeah, I agree with you, jiawen. It's incomprehensible to me how puny little humans can deduce so much about the universe.
posted by InsertNiftyNameHere at 7:33 PM on July 11, 2013


The universe is magically delicious.
posted by not_on_display at 9:36 PM on July 11, 2013


Is there any reason to think this feature is unique to our solar system? The shape is formed by the wind speed differential between the poles and equator. Seems that other stars would exhibit similar tails.
posted by troll at 9:41 PM on July 11, 2013


InsertNiftyNameHere: Why is there a magnetic field in interstellar space? And WTF is so massive that is generating it? Super massive black hole at the center of the galaxy?

So, a common-ish joke in the field is that magnetic fields for Astrophysicists are like sex for Psychologists. That is, hugely important, extremely prevalent, but also messy and difficult to understand precisely.

Thats not to say that we don't understand electromagnetism, we do really really well actually, but the effects and impacts of them get very chaotic very quickly when you try to do things like numerical simulations which are one of the big ways that astronomy goes from what to how.

From a physics 101 level, our galaxy has a magnetic field for the same reason that our star has one, and the earth has one. That is, you have a bunch of electrically charged material moving around. In the earth, this is the molten metal core. For the sun, this is a bunch of ionized Hydrogen inside of it. For the galaxy, its all sorts of things, but mostly the hot ionoized gas between some stars. (Also though, at a much much much lower level, the stars magnetic fields inside the galaxy itself, and accretion disks around black holes, sure, etc). So a basic tenet of EM is that a changing electric field gives rise to a changing magnetic field. This is how electric motors work, ne? So charged particles moving (ionized atoms) gives rise to a changing electric field gives rise to a magnetic field. This is called a Dynamo and is sort of our best explanation for most of these types of fields (Mars is different, for example, it has no liquid core but has a very weak magnetic field from what is probably some baked in magnetism, like a bar magnet, in its crust. I am not your planetary physicist, etc etc.). That's pretty much the why they exist.

So the solar wind is ionized Hydrogen (essentially protons) that flow out along the magnetic field lines of the sun. They have a density and temperature essentially, and in many ways act like a fluid. They push against the gas and dust from elsewhere in the galaxy, which is what this whole heliosphere/pause/bowshock business is about. The thing is, all of these systems are rotating, and differentially (so not all at the same rate), which means that the magnetic field lines get tangled. Which is just an easy way of saying that things get very complex as turbulent effects start in. This makes things very messy, which is where magnetic fields get hard (chaotic, turbulent effects), and is exactly why we need observations like this, to understand

cjorgensen: How does this benefit mankind?
One of the awesome things about space is that its big, and often times quite hot and/or cold, and it can be very very dense, or very very empty. So basically, its a giant physics lab that lets us look at physical effects that we cannot recreate in a lab on earth. Much of modern day space physics and astro physics is focused on how the physics of these weird, complex systems work. And, very often that relates back to questions like: what are the limitations in our understanding of current physical theories, or where does our understanding of some aspect of physical science science break down? So, most of the time, we feel that this kind of work is important because its a method of increasing of physical understanding of the universe. How, and why, things work. This is just the quintessential argument of understanding how things work lets us make new things that we couldn't have without this understanding that lies behind all basic fundamental research. Its the same argument that the people at CERN would make essentially. (Or the whole Einstein-General Relativity-GPS connection that is a fantastic example). And this is aside and in addition to the more geographical argument of "We should explore to know what exists as that enriches our lives and could potentially have some material payoff" argument.

In this particular case, this is an interesting test case for our understanding of magneto-hydrodynamics essentially.

Plus, the tools developed to do this often can have a more near term real world impact. It turns out that the same codes model nuclear bombs, exploding stars, and power generating fusion and/or fission reactions for example.
posted by McSwaggers at 12:32 AM on July 12, 2013 [12 favorites]


McSwaggers: "So, a common-ish joke in the field is that magnetic fields for Astrophysicists are like sex for Psychologists. That is, hugely important, extremely prevalent, but also messy and difficult to understand precisely. "

Many thanks! This stuff blows my mind.
posted by InsertNiftyNameHere at 1:05 AM on July 12, 2013


"Why is there a magnetic field in interstellar space? And WTF is so massive that is generating it? Super massive black hole at the center of the galaxy?"

I'm sadly very much a layman these days, but I suspect the effect is something like the winds of Neptune. When Voyager's observation of the winds on Neptune came in, people were shocked that the furthest gas giant in our solar system (and therefore coldest, least energetic) had some of the highest wind speeds. We're pretty sure now that the reason is due to how far Neptune is from the Sun; the winds were able to gradually ramp up in speed over millions-billions of years, thus reducing the braking effects from the turbulence that might have developed in a more energetic system.

Similarly, the galaxy is sort of an ionic soup with these little point sources of both magnetic force and charged particles. And it's been spinning for ages. I don't know if you grew up somewhere with a swimming pool, but I remember getting all the kids in my town to circle our modest municipal pool over and over until we created a firm, noticeable current*. The stars in the Milky Way have been stirring their pool for billions of years. You don't need a powerful, supermassive magnetodynamo to create a strong (or even just noticeable) field if you've got that kind of time.

* if you've never done this, let me propose a POOL PARTY! =D
posted by Eideteker at 7:50 AM on July 12, 2013 [1 favorite]


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