Boffins claim Voyager has already left the Solar System There's a boffin battle brewing at the fringe of the Solar System. At issue is whether the venerable Voyager 1 spacecraft has left the region where Sol's electromagnetic winds blow, or is still in the tiny pocket of space we call home. The “we're outta here” camp has penned a letter in The Astrophysics Journal titled “A …
Put two magnets near each other, and their fields line up, reorienting the magnets positions.
Kind of makes sense that eventually a star would orient its field to the galactic one.
After all, isn't the galactic field just the sum of all the fields of the stars, neutron stars, magnetars, quasars, what-have-you, anyway? And all those fields'll be seeking equilibrium.
I take it that you are not aware that the sun's magnetic field inverts every eleven years or so then?
"Am waiting for the crash and tinkle when it hits the crystal sphere"
It's happened, but the sound hasn't reached us yet.
To anybody thinks there's no sound in space: you're wrong; it's just very, very, very quiet.
Up till now it's all been models.
I'm not sure how well they work at what I presume are very low and very large interacting magnetic fields.
Thumbs up for explaining how some of the signs of leaving the solar system could be detected and not others.
As a physicist observed about another debate "We are in a state of such confusion we will definitely learn something"
... McKibben at al noted that the boundary layer pulses in response to the solar minimum/maximum by as much as 150AU, (paper here). Also, we're observing that the sun is about to go through a magnetic inversion. The heliopause might catch up and pass Voyager again.
The press reporting seems to expect something definitive, like a 'wall' in space, but that's a silly analogy - it's more like a sponge that soaks and dries out, with occasional big squeezes when it all lines up together. Voyager is just taking another wash on the edge of the solar system basin... nothing like a wall.
:-)
Believe it or not, if it took gravity any time to reach us, the earth would be orbiting where the sun WAS when the gravity left the sun. Regardless of the time involved, the result would be an unsustainable orbit. We would spiral into the sun or off into space. Every appropriate experiment shows that earth's orbit is around where the sun really is. So you have a choice, either gravity is instantaneous, or gravity as a 'thing' doesn't exist, but is actually a curvature of space caused by mass -as postulated by Einstein. Or maybe something even stranger...
Very likely there will be no sharp transition to be found, much like the 'transition' from Earth's atmosphere to outer space. Last I had heard, space begins at 100km altitude, because it is a nice round number, but atmosphere is still detectable beyond that point.
We may simply define interstellar space as beginning at some distance agreed upon, again much like "wogs begin at Calais".
Very likely there will be no sharp transition to be found, much like the 'transition' from Earth's atmosphere to outer space. Last I had heard, space begins at 100km altitude, because it is a nice round number, but atmosphere is still detectable beyond that point."
I agree. There will always be debate, even if there is a consensus definition, about where the edge of the solar system is. It will always be an arbitrarily defined sphere simply because it's not a "wall". The location of where the solar wind balances out against incoming "galactic wind" is sure to vary over time so the definition of the edge of the solar system is, by definition, a variable within limits.
Who's to say that the consensus won't evolve to be the out reaches of Plutos orbit? Or some other arbitrary factor.
"Very likely there will be no sharp transition to be found, much like the 'transition' from Earth's atmosphere to outer space..."
Good point. This is why many cite the altitude record-setting X15 flights as "space" flights as they reached or exceeded 100km:
http://www.astronautix.com/flights/x15ght91.htm
"...Unofficial world altitude record. Maximum Speed - 6105 kph. Maximum Altitude - 107960 m. Second X-15 astronaut flight (FAI definition); fifth astronaut wings flight (USAF definition)..."
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They make it sound like they're expecting the craft to come across a big fence with a border crossing checkpoint on it, with a little green man in a flying saucer waiting to check its passport. Plus probably a big sign saying "the Universe welcomes careful fliers" or something.
It almost sounds like they're expecting a demarcation point as accurately defined as the US Canada border, even in the wilderness.
(If you've never seen the pictures, whack 'forest border between United States and Canada' into your favorite image search engine).
Yup, that is just friggin' sad.
Worse still, you're not even allowed intimate contact with your significant other while cross-border rambling.
Well...
One of the NIAC presentations to NASA was an investigation into (IIRC) using solar sails for this and with a Voyager sized payload they reckoned they could get from Earth to where Voyager is in about 10 years, not 35 to 40 years.
IIf you did that a Voyager 2.0 mission could do this one of 2 ways. 1)Same instrument suite but implemented with modern technology, giving the same capability at much smaller size (handy as there are no more Titans available, although a Delta IV Heavy would probably as well, and a F9H definitely would help). JPL has been busy in 4 decades gradually whittled the weight down quite a bit.
Or keep them and add a bunch more.
I'll take a wild stab here and say they won't be staying with the the nibble serial 16 bit CMOS processor (1 4 bit ALU chip with lots of registers clocked at 4KHz. No that 's not a typo) architecture.
One of the NIAC presentations to NASA was an investigation into (IIRC) using solar sails for this and with a Voyager sized payload they reckoned they could get from Earth to where Voyager is in about 10 years, not 35 to 40 years.
I think I can see an issue with using solar sails: beyond the heliopause they become interstellar-medium sails and the probe gets blown back again. Or way off course. Or somewhere.
"I think I can see an issue with using solar sails: beyond the heliopause they become interstellar-medium sails and the probe gets blown back again. Or way off course. Or somewhere."
No problem - eject said solar sails, and switch to nuclear power.
Concerning the heliosphere, we know nothing, for the time being we only have educated guesses.
Now we are learning about it while going through it - it is going to take some time and there will be heated debate before a consensus is reached. So let us just note that new theories about the heliosphere are forming, which is a good thing, and monitor scientific progress for the next five years without worrying too much about it.
In the next decade, scientists will have worked it out. In the meantime, it's just too soon to comment.
6 centuries from now the Earth will get an Penalty Charge Notice from little green Enforcement Officer for littering and a court summons with note of 2500 space credits and possible criminal record for space littering.
Then we gonna get some green ballifs coming in and impounding moon for non paying up!
The solar system ends with the Oort cloud that reaches about 50000 AU from the sun
http://en.wikipedia.org/wiki/Oort_cloud
You are an american?
Only americans give a shit if Pluto is a planet or a plutoid.
No matter what you call Pluto, it still orbiting the sun and don't give a shit what it's called
True enough. What the scientific argument is about is if the probes have left the magnetic bubble created by Sol.
As for Pluto, doesn't matter where I observe it, even if it were under foot. This American firmly believes that it is simply a smallish chunk of rubble that isn't on anything resembling a planetary orbit that corresponds with the planets of this solar system.
It's only rubble left behind from the old mass relay. ;)
Voyager 1 is about 125 AU from the sun.
Sednas aphelium is about 1009 AU from the sun.
Many of our comets aphelium is 10000 AU to 20000 AU from the sun
Oorts cloud is reaches about 50000 AU or one light year from the sun
Just because protons can not leave the sun's gravitational field does not mean that the solar system ends.
It just means that the sun's gravitational field really reach out there and even longer.
Wake me when Voyager 1 actually leaves the solar system.
It ought to be about year 16,013 after Christ
What we absolutely know for certain is that Voyager is most definitely outside of the solar system. Unless it's still inside of the solar system.
The only way we'll be certain is with a shitload more measurements over the course of months to years, possibly even a decade.
But, for each inch the probes move outward, we forge new scientific measurements and new firsts.
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