Where does the Solar System end?

25,769,002,025

kilometres · Voyager 1's distance from the Sun

It depends on what you mean by the edge. The planets stop at Neptune, 30.0690 AU from the Sun. The Sun's wind stops at the heliopause, roughly 120 AU out, where both Voyagers crossed into interstellar space. The Sun's gravity still holds the Oort cloud, which may reach 100,000 AU.

Right now Voyager 1 is 25.8 billion kilometres from the Sun, past the heliopause and still moving out.

Time since Voyager 1 went interstellar

14y 71d 4h

Measured

Time since Voyager 2 went interstellar

7y 364d 22h

Measured

Voyager 2's distance from Earth

21,642,318,263 km

Measured

Live · as of 4 Nov 2026

Time for light from Earth to reach Voyager 1

23h 58m 08s

Measured

Live · as of 4 Nov 2026

What the edge means

Three edges, not one

The Solar System is the Sun and everything it holds on to: eight planets, their moons, and countless smaller icy and rocky bodies. Asking where it ends is like asking where a town ends. There is the last house, the edge of the streetlights, and the line on the map, and they are in different places.

The first edge is the last planet. Beyond Neptune lies the Kuiper belt, a ring of icy worlds that thins out around 50 AU. The second edge is where the Sun's wind gives way to the gas between the stars. The third is where the Sun's gravity stops being the strongest pull around.

NASA uses the second edge when it says the Voyagers reached interstellar space. Yet NASA also calls the Oort cloud the most distant region of our Solar System. Both are true. They answer different questions.

30.0690 AUNeptune's average distance from the Sun

The heliosphere

The bubble we live in

The Sun blows a constant wind of charged particles in every direction. It leaves at hundreds of kilometres per second and carries the Sun's magnetic field with it. That wind inflates a huge bubble around us called the heliosphere.

Far out, the wind meets the thin gas between the stars. First it slows sharply at a boundary called the termination shock. Then, at the heliopause, it stops pushing outward at all. The heliopause is roughly 120 AU from the Sun. Sunlight takes about 17 hours to get there.

The bubble is not round. The Sun moves through the galaxy, so the bubble is squeezed on one side, like a boat's bow wave. How long its tail is, and whether it has one at all, is still debated.

120 AUDistance from the Sun to the heliopause, where the Voyagers crossed it

25 August 2012 · 5 November 2018

Two crossings, six years apart

Voyager 1 reached the termination shock on 16 December 2004, at 94.0 AU from the Sun. Voyager 2 reached it on 30 August 2007, at 83.7 AU. Voyager 2 met it much closer to the Sun, the first clear sign that the bubble is lopsided.

Voyager 1 crossed the heliopause on 25 August 2012, at 121.6 AU. Voyager 2 followed on 5 November 2018. On that day its instruments counted far fewer of the low-energy particles that come from the Sun, and more cosmic rays from the rest of the Milky Way. The Sun's wind was behind it.

119.0 AUVoyager 2's distance from the Sun when it crossed the heliopause

The Oort cloud

How far the Sun's gravity reaches

Past the heliopause, the Sun's gravity still rules. Far beyond it, astronomers think a vast, thin shell of icy bodies surrounds us: the Oort cloud. No one has seen it directly. We infer it from the long, steep orbits of comets that fall in from it.

NASA puts its inner edge somewhere between between 2,000 and 5,000 AU from the Sun. The outer edge may lie as far as 100,000 AU, though NASA gives a wide range. Out there, the pull of nearby stars and of the galaxy itself starts to match the Sun's. That fuzzy line is the widest answer to our question, and nobody knows exactly where it falls.

New Horizons, heading the same way more slowly, is still inside the bubble.

2,000 AUDistance from the Sun to the inner edge of the Oort cloud

Voyager 1, from here on

A very long trip

Voyager 1 moves away from the Sun at about 16.92 kilometres per second. Even so, it will need roughly about 300 years just to reach the inner edge of the Oort cloud. Crossing the whole cloud would take it something like about 30,000 years.

So by the widest answer, nothing we have built has left the Solar System yet. By NASA's interstellar answer, two have. Both spacecraft keep sending data from beyond the heliopause.

300 yearsTime for Voyager 1 to reach the inner edge of the Oort cloud

Why the bubble matters

The shield around us

The heliosphere is more than a border on a map. Its magnetic field turns many cosmic rays away, the fast particles flung out by exploding stars across the galaxy. The Voyagers saw this when they crossed. The number of cosmic rays they counted jumped once they were outside.

Earth's own magnetic field and air do the rest. We live inside two shields, one of them about 120 AU wide on its near side. Every planet, every life on Earth, has always sat within the Sun's bubble.

14y 71d 4hTime since Voyager 1 went interstellar

In perspective

100,000 AUDistance from the Sun to the outer edge of the Oort cloud

About 1.6 times a light-year.
About 833 times the distance from the Sun to the edge of the solar wind.
If the Sun were a grain of sand, this would be about 5.4 kilometres.
About 529 times the distance around Neptune's orbit.
If Earth were a grain of sand, this would be about 586 kilometres.
Light would take 1.6 years to cover it.
If the Moon were a grain of sand, this would be about 2,200 kilometres.
The International Space Station in orbit would take 62,000 years to cover it.
A rifle bullet leaving the barrel would take 500,000 years to cover it.

Everything you have ever known has happened inside the Sun's bubble. What would you want to know about the space just beyond it?

Your sky

The sky above you, right now

Every star, planet and constellation over your head at this minute, drawn for where you are.

See your sky →

Questions people ask

At what point does the Solar System end?

There is no single line. The planets end at Neptune, the Sun's wind ends at the heliopause about 120 AU out, and the Sun's gravity reaches into the Oort cloud, perhaps as far as 100,000 AU.

What is the edge of a solar system called?

For the Sun's wind, the edge is the heliopause, the outer wall of the bubble called the heliosphere. Inside it is the termination shock, where the wind first slows. For gravity, there is no special name; the outer edge of the Oort cloud is the usual answer.

What did NASA find at the edge of the Solar System?

When each Voyager crossed the heliopause, particles from the Sun dropped away and cosmic rays from the galaxy rose. Voyager 2 met the termination shock 83.7 AU from the Sun, closer than Voyager 1 did, which showed that the bubble is lopsided.

Is the Oort cloud the edge of the Solar System?

By the gravity answer, yes. NASA calls it the most distant region of our Solar System, with its inner edge between between 2,000 and 5,000 AU. It is still a theory, inferred from comets, not seen directly.

Can we ever realistically leave the Solar System?

Voyager 1 has left the Sun's bubble, but at its speed it needs about 30,000 years to pass the Oort cloud. Leaving by the widest definition would take any craft we can build today many thousands of years.

How do we know?

Every number on this page has a source

Show the 32 numbers and their sources

Fact	Value	Certainty	Source	As of
Diameter of a grain of sand	0.5 mm	Estimated	USGS	27 Oct 2026
Distance from the Sun to the heliopause, where the Voyagers crossed it	120 AU	Estimated	American Geophysical Union Nature Astronomy NASA	27 Oct 2026
Distance from the Sun to the inner edge of the Oort cloud	2,000 AU	Debated	NASA	4 Nov 2026
Distance from the Sun to the outer edge of the main Kuiper belt	50 AU	Estimated	NASA	27 Oct 2026
Distance from the Sun to the outer edge of the Oort cloud	100,000 AU	Debated	NASA	27 Oct 2026
Distance to Proxima Centauri	4.2465 ly	Measured, with error	ESA Astronomy & Astrophysics ESA	1 Jan 2016
Earth's average distance from the Sun	1.0000 AU	Measured	NASA NSSDCA	1 Jan 2000
Earth's diameter at the equator	12,756 km	Measured	NASA NSSDCA	27 Oct 2026
Jupiter's average distance from the Sun	5.2034 AU	Measured	NASA NSSDCA	1 Jan 2000
Jupiter's diameter at the equator	142,984 km	Measured	NASA NSSDCA	27 Oct 2026
Length of a light-year	9,460,730,472,580.8 km	Measured	NASA JPL Solar System Dynamics	27 Oct 2026
Length of Neptune's orbit around the Sun	28,260,000,000 km	Measured	NASA NSSDCA	27 Oct 2026
Neptune's average distance from the Sun	30.0690 AU	Measured	NASA NSSDCA	1 Jan 2000
Speed of light in a vacuum	299,792.458 km/s	Measured	BIPM	27 Oct 2026
The International Space Station's orbital speed	7.66 km/s	Measured	CelesTrak NASA	27 Oct 2026
The Moon's mean diameter	3,474.8 km	Measured	NASA NSSDCA	27 Oct 2026
The Sun's mean diameter	1,391,400 km	Measured, with error	NASA NSSDCA International Astronomical Union / The Astronomical Journal	27 Oct 2026
Time for light from Earth to reach Voyager 1	23h 58m 08s	Measured	NASA JPL	4 Nov 2026
Time for Voyager 1 to pass beyond the Oort cloud	30,000 years	Estimated	NASA	18 Oct 2026
Time for Voyager 1 to reach the inner edge of the Oort cloud	300 years	Estimated	NASA	18 Oct 2026
Time since Voyager 1 went interstellar	14y 71d 4h	Measured	NASA American Geophysical Union	25 Aug 2012
Time since Voyager 2 flew past Neptune	37y 71d 6h	Measured	NASA NASA JPL	25 Aug 1989
Time since Voyager 2's launch	49y 75d 19h	Measured	NASA NASA NSSDCA	20 Aug 1977
Time since Voyager 2 went interstellar	7y 364d 22h	Measured	Nature Astronomy Nature Astronomy NASA	5 Nov 2018
Typical muzzle velocity of a rifle bullet	945 m/s	Estimated	Headquarters, Department of the Army	27 Oct 2026
Voyager 1's distance from the Sun	25,769,002,028 km	Measured	NASA JPL	4 Nov 2026
Voyager 1's distance from the Sun when it crossed the heliopause	121.6 AU	Measured	American Geophysical Union NASA JPL NASA	25 Aug 2012
Voyager 1's distance from the Sun when it crossed the termination shock	94.0 AU	Measured, with error	NASA NASA JPL	16 Dec 2004
Voyager 1's speed relative to the Sun	16.92 km/s	Measured	NASA JPL NASA	18 Oct 2026
Voyager 2's distance from Earth	21,642,318,268 km	Measured	NASA JPL	4 Nov 2026
Voyager 2's distance from the Sun when it crossed the heliopause	119.0 AU	Measured	Nature Astronomy Nature Astronomy NASA JPL NASA JPL	5 Nov 2018
Voyager 2's distance from the Sun when it crossed the termination shock	83.7 AU	Measured, with error	Nature NASA NASA JPL	30 Aug 2007