WASHINGTON: The solar system may not be a nice round shape, but rather a bit squashed and oblong, according to data from the Voyager 2 spacecraft exploring the solar system’s outer limits, scientists said on Wednesday.

Launched in 1977, the Voyager 1 and Voyager 2 unmanned probes are now studying the edges of the heliosphere, the huge magnetic ‘bubble’ around our solar system created by the solar wind as it runs up against the thin gas in interstellar space.

The solar wind is made up of electrically charged particles blown into space in all directions by the sun. The boundary between the heliosphere and the rest of interstellar space is known as the ‘termination shock.’

Voyager 2 in August 2007 crossed this boundary 7.8 billion miles (12.5 billion km) from the sun.

Voyager 1 had crossed the boundary in December 2004 about 10 billion miles (16 billion km) away from Voyager 1 and almost a billion miles (1.6 billion km) farther from the sun.