Here's What It Means When NASA Says Voyager 1 Is In Interstellar Space

This image from NASA puts the latest Voyager 1 announcement - that it has entered interstellar space - in the perspective of the whole solar system.

The scale is in astronomical units (AU). One AU is equal to the Earth's distance from the sun - about 93 million miles. It's also in log scale, which means that each increment increases the measurement by a factor of ten. You can see the distance on the map from 1 to 10 is the same as the distance between 10 and 100 - even though one is a distance of 9 AU and the other is 90 AU.

When most people talk about the solar system, they are usually talking about the space from the sun to the last planet. However, scientists agree that the solar system actually extends all the way out to the Oort Cloud: a giant cloud that generates comets that pass by the sun.

So, just because Voyager has entered interstellar space, doesn't mean it has left the solar system. It still has to pass through the huge expanse of the Oort Cloud, which you can see in the image. The inner edge of the Oort Cloud is estimated to be about 1,000 AU from the sun, while its outer edge is 100,000 AU away.

Until Voyager passes the Oort cloud, it will still be under the influence of the the gravity of our sun - and still technically in our solar system. It will take about 300 years to get to the inner edge of the Oort Cloud, and tens of thousands of years to get past it.