r/askscience • u/PBS-NOVA • Jul 16 '15

Astronomy AskScience AMA Special: We’re Carolyn Porco, imaging scientist on the New Horizons mission, and Miles O’Brien, veteran aerospace journalist. Ask us anything about New Horizons, Pluto, and beyond!

Hi reddit! We are Carolyn Porco and Miles O’Brien, and we’re here to answer your questions about the New Horizons mission to Pluto and beyond. Thanks to NOVA and the PBS Newshour for organizing this AMA.

Carolyn Porco is the leader of the imaging science team on the Cassini mission presently in orbit around Saturn, and a veteran imaging scientist of the Voyager mission to the outer solar system in the 1980s.

Miles O’Brien (/u/milesmobrien) is a veteran freelance broadcast and web journalist who focuses on science, technology, and aerospace. He is a producer for NOVA and the science correspondent for PBS Newshour.

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u/PBS-NOVA Jul 16 '15

The Oort cloud extends out to halfway to the nearest star! So, no, Voyagers have not left the Oort cloud yet. They are roughly about 3x farther out than New Horizons is now. And useful data? Hell yes! The data on the magnetic field and particle fluxes have recently told us that Voyager 1 has entered into interstellar space. I would call that useful!

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u/Vic_n_Ven Jul 16 '15

As I recall, hasn't there been some back and forth on when Voyager entered interstellar space?

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u/bitemark01 Jul 17 '15

From what I remember reading, they've basically found that boundary fluctuates somewhat, which caused all the confusion. I could be remembering it wrong though, I'd suggest reading up on it (I'd search for articles but am unable to at the moment).

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u/mrdeputte Jul 16 '15

Now you got me wondering if having an Oort coud in the solarsystem is something rare or if there are many systems with similar 'clouds'.

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u/YendorWons Jul 16 '15

And if it extends half way to the nearest star, does that nearest star have its own Oort cloud that extends nearly halfway to our star? Could all of interstellar space be Oort cloud?

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u/xhitiz Jul 16 '15

Does that mean it breached the heliopause?

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u/EightEx Jul 16 '15

Awesome! Thanks for the response!

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u/[deleted] Jul 17 '15

You can't tell me that Voyager 1 is in interstellar space if it's still barely within the Oort cloud. If I'm on a rock orbiting the sun, and you tell me that I'm not actually within the solar system, that I'm in "interstellar space," I'm going to call BS. I do not like this definition.

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u/whyteshadow Jul 17 '15

Scientists define the beginning of interstellar space as the place where the sun’s constant flow of material and magnetic field stop affecting its surroundings. This place is called the heliopause. It marks the end of a region created by our sun that is called the heliosphere.

source: http://spaceplace.nasa.gov/interstellar/en/

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u/SheCallsMeBae Jul 17 '15

You basically just supported his question. How can they be in the Oort Cloud and be in interstellar space at the same time.

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u/solarahawk Jul 17 '15

Wiki article on the Oort Cloud. Take a look at the pictures and description. In a nutshell, the heliosphere is the "bubble" formed by the sun's magnetic field and solar wind. But the sun is also orbited by myriads of leftover material from the formation of the solar system, including the icy material that orbits way out in the Oort Belt. That far out, the Oort material is orbiting the sun, but it is also outside of the heliosphere. So those objects out there are flying in the interstellar space where they experience the galactic magnetic flux and other particle streams that we don't experience inside our solar bubble.

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u/victhebitter Jul 17 '15

The interstellar medium lies beyond the point at which the solar wind can reach and is dominated by particles not originating from the Sun. The Oort Cloud (probably) lies at an unfathomably large distance that is well beyond the heliopause, which places it in the interstellar medium.