[skvj]

Here's a great illustration of Voyager 1 and Voyager 2 outside of the heliosphere: https://www.nasa.gov/press-release/nasa-s-voyager-2-probe-en...

[SenHeng]

Is there a reason why the left side of the heliosphere is so elongated?

Is it simply because we haven't sent any probes there and so don't really know where it ends or is it really this oblong shaped?

[petschge]

Because the solar system is moving relative to the local interstellar medium. So effectively you get a "headwind".