Nasa's Voyager 2 Probe 'Leaves the Solar System' (bbc.co.uk)

The Voyager 2 probe, which left Earth in 1977, has become the second human-made object to leave our Solar System. From a report: It was launched 16 days before its twin craft, Voyager 1, but that probe's faster trajectory meant that it was in "the space between the stars" six years before Voyager 2. The news was revealed at the American Geophysical Union (AGU) meeting in Washington. And chief scientist on the mission, Prof Edward Stone, confirmed it.

He said both probes had now "made it into interstellar space" and that Voyager 2's date of departure from the Solar System was 5 November 2018. On that date, the steady stream of particles emitted from the Sun that were being detected by the probe suddenly dipped. This indicated that it had crossed the "heliopause" -- the term for the outer edge of the Sun's protective bubble of particles and magnetic field. And while its twin craft beat it to this boundary, the US space agency says that Voyager 2 has a working instrument aboard that will provide "first-of-its-kind observations of the nature of this gateway into interstellar space".

Comments

Maybe not

[Impy the Impiuos Imp]

second human-made oblect to leave the solar system

I wonder if there isn't some chunk of arrowhead embedded in an asteroid smashed off the Earth in some titanic collision.

Re:Maybe not

[110010001000]

Yeah, it is possible that in the 8,000 years of Earth's history that happened at least once.

Re:Maybe not

[110010001000]

Well maybe. I'll check the Bible to see if there is any record of it occurring.

Re:Maybe not

[Gravis Zero]

I wonder if there isn't some chunk of arrowhead embedded in an asteroid smashed off the Earth in some titanic collision.

1) A collision of that magnitude (large enough to create ejecta) would likely be a mass extinction event. Humans have yet to experience one of those (from an asteroid).
2) Other planets (especially Jupiter) would likely ensnare the newly created asteroid. Getting past them once is very unlikely to start with but getting past them, being just the right size to not cause a mass extinction event but large enough to create ejecta, then have the ejecta (now asteroid) getting past those same planets and all in the span in the last 100k years (hell, I'll give you all 400k years for proto-humans) and there being no recognizable evidence? Finding a unicorn being ridden by a leprechaun seems more likely.

The chances of this happening are slim to start with but the chances of this happening while humanity existed and there being no clear evidence of it are beyond infinitesimally small. It's a neat thought experiment but that's all it is.

Re:Maybe not

[SWPadnos]

That's odd. I searched for "meteorite" in the Bible and there weren't any results.

Did you search the original Hollerith version, or were you using the updated Unicode version?

You've got to remember that there have been several translations (through EBCDIC and ASCII, with a short diversion through UTF8), and there's no direct translation for "meteorite" (the closest would be "comet" (U+2604, U+FE0F) or "shooting star" (U+1F320)).

Gotta be careful when electronically searching ancient texts!

Re:Maybe not

[Gravis Zero]

The chances of a random object shot out from earth being caught in Jupiter's gravity well is essentially zero. Space is big!

Sure, space is big but planets are moving very fast (relatively). It's like trying to stick your finger in an active industrial fan and pulling it out before a fan blade gets you. You're going to lose a digit.

Re:Maybe not

[cheesybagel]

Quite a lot of stories in the Ancient Testament are basically lifted from older stories from the Middle East. Like how Noah's Ark is taken from an episode in the Epic of Gilgamesh.

In another example, the Vedas (Hindu sacred teachings), used to be transmitted orally for several thousand years until they were written down much later.

A lot of the knowledge we have from Greek myths is also a transcription of oral transmitted stories including Homer's Illyad and the Trojan War. The Indian Mahabharata may be another orally transmitted ancient war story.

Re:Maybe not

[K. S. Kyosuke]

To escape the solar system, allowing for earth's orbital velocity, you need to be expelled from the surface at more than double that speed.

That's actually almost meaningless. You can no more achieve 17 km/s than you can achieve 11 km/s. Basically the problem is that the combination of high velocity and dense atmosphere at low altitude AND passive flight after ejection means you need to reach a HIGH initial velocity with a LARGE solid object (to survive the atmospheric exit), but that's only possible with a truly massive impact as you point out. In addition, besides hitting Earth in the first place, it would also probably have to hit a place where human artifacts are present in a protective sedimentary rock (to survive the ejection). Which means that the impactor would have to have hit very recently a place where there was human presence very early on - which is a small part of Africa, not the whole surface of Earth. We know of no such events, and in this case, it very likely means that no similar event happened.

41 years

[110010001000]

41 years to exit the solar system. 13 billion miles. Max speed 36,000 mph. 0.00005% the speed of light. Pretty cool!

Re:41 years

[k6mfw]

You have summed up just how big our Solar System is and yet puny compared to the Milky Way galaxy (nice post). Though a screamer at 36K mph, a fraction of a snail's pace in terms getting to another star. Overall to think it was launched so many years ago, and think about various items on the spacecraft with company tags with model and serial numbers, and many of these companies no longer existing.

Re:41 years

[110010001000]

The fastest man made object will be the modern Parker probe at 430,000 mph. That is 0.0006% the speed of light. To get to Alpha Centauri it would take 6810 years. There is no point trying to go to Alpha Centauri. Nothing would make the trip.

Re:41 years

[meglon]

A space probe made of Twinkies, piloted by cockroaches.

Re:41 years

[Kjella]

Though a screamer at 36K mph, a fraction of a snail's pace in terms getting to another star.

Yeah. The moon was hard. Mars is hard. But going interstellar... even if SpaceX built the BFR, boosted it to the max in a high elliptic orbit, put another stage on top instead of the BFS and sent it on the Grand Tour of gravity slingshots (which won't happen again until 2150, but that's still a small problem) it'll go from 40000 years like Voyager to what, like 10000 years? Chemical rockets are almost like breeding horses to reach the moon. But I do hope they'll limp humans to Mars in my lifetime...

Re:41 years

[Nkwe]

2 years to get from Earth to Jupiter, 2 more to Saturn, 4.5 to Uranus, 3.5 to Neptune, and an astonishing 29 to reach interstellar space. Truly amazing.

Agreed. Also amazing that it is still operating after all these years and harsh conditions. That was some seriously good engineering done 40+ years ago.

Amazing!

[gosand]

This really is an amazing thing. And I mean that in the truest sense, not in an OMG-this-pumpkin-spice-frappachino-is-amazing kind of way. Sadly, I am guessing most people won't even read this story because it's not trash news.

I really liked this from the article: "Voyager 1 will not approach another star for nearly 40,000 years, even though it is moving at such great speed. "

It's fascinating and hard to comprehend.

Re: Amazing!

[dgatwood]

You missed your chance to quote Douglas Adams.

"Space is big. Really big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist, but that's just peanuts to space."

Voyager 2 hasn't really left the solar system

[northbrae]

Voyager 2 has entered interstellar space (i.e. crossed the heliopause, the boundary where the Sun's solar wind is stopped by the interstellar medium), but it hasn't left the solar system (the spherical area of space gravitationally bound to the Sun). The Oort Cloud, by current estimates, extends 10-2,000 times farther out than Voyagers 1 & 2 are now. The probes are expected to reach the inner edge of the Oort Cloud in ~300 years. The popular idea of the solar system ends at Pluto, but we know of many objects orbiting far beyond that.

Re:Voyager 2 hasn't really left the solar system

[itzdandy]

Inertia doesn't care about the gravity from the 'void' beyond the solar system. Out in the oort, objects are orbiting so slowly that the micro-gravity from the sun still keeps them. The gravity from the void beyond is a tiny fraction comparatively. So this is about inertia vs gravity, not local gravity vs interstellar gravity.

Also consider that the oort cloud has not been observed. 'cloud' might be a very optimistic description of what orbits out there, if anything. A single icy body out there could be the source of all of these oort cloud comets.

Obligatory XKCD

[CapeBretonIslander]

Voyager 2 will have some catching up to do to leave the solar system as many times as Voyager 1. :) https://xkcd.com/1189/

More tools this time through

[Tablizer]

Voyager 2 has an additional instrument that Voyager 1 lacked during its crossing:

The most compelling evidence of Voyager 2's exit from the heliosphere came from its onboard Plasma Science Experiment (PLS), an instrument that stopped working on Voyager 1 in 1980, long before that probe crossed the heliopause.

Re:For small values of 'Solar System'

[dissy]

Agreed. I understand there's a Public Relations consideration in these announcements, but the real, final, inarguable milestone would be connected to the gravitational influence. It will have escaped the solar system when it's at a place where an object couldn't be held in orbit around the Sun. (How far away is that anyway?)

The suns gravitational influence ends at the outside edge of the heliosphere, which is about 100 AU from the sun. This is what most everyone labels as "the edge of the solar system"

The oort cloud starts about 10000 AU from the sun and is not under the suns influence in any way.
It also kind of makes the anon parent post a bit silly.
Any small or large value for 'solar system' will still be FAR closer to the sun than the oort cloud is.

Also keep in mind the oort cloud is insanely thick, starting just under 10000 AU and ending about 100000 AU away.

Alpha Centauri is two orders of magnitude closer to the outer most boundary of the oort cloud than our sun is.
Any definition of our solar system that includes the oort cloud would also be including numerous other solar systems and stars, completely nullifying any reason for having such a definition in the first place.

Re:Time to send something new.

[penandpaper]

Did you miss New Horizons?

If you missed the Pluto flyby there will be another flyby of a Kuiper Belt Object ((486958) 2014 MU) on January 1, 2019.

Moving at 36,373 mph and heading toward the direction of the constellation Sagittarius. It will be the 3rd man made object to leave the solar system.

Obligatory xkcd

[giampy]

https://xkcd.com/1189/