Why cant you go inside other plannets like jupiter and pluto instead you go ontop of it. Why is this?

Question: Why cant you go inside other plannets like jupiter and pluto instead you go ontop of it. Why is this?
- Keywords:
  jupiter,
  planet,
  pluto
Asked by emmagrace to Dalya, Derek, Sarah, Tim, Tom on 21 Jun 2011.
- Derek McKay-Bukowski answered on 20 Jun 2011:
  
  This depends on the planet.
  
  Rocky planets, like Mercury or Mars, are solid. Unless you find a cave, you cannot get inside the planet.
  
  Big planets, like Jupiter or Saturn, are gas, sure. You can start to go into this, but the pressure builds up extremely quickly and it would crush you and your spaceship. Additionally, unless you have very powerful rockets, the friction of the atmosphere would slow your spaceship down and you would be pulled down deeper into the planets atmosphere because you could no longer keep your orbit going. Then you would be crushed by the pressure.
  
  By the way… astronomers don’t regard Pluto as a planet any more (they made a mistake, oops!). However it is probably rocky like Mercury and so you’d need to find a cave to get under the surface.
- Tom Crick answered on 20 Jun 2011:
  
  Great answer by Derek already — some of the bigger planets in the solar system (Jupiter, Saturn, Uranus, Neptune) are made of gas (possibly with a dense core) so you can’t really go on top of it — there’s no distinct “top”!
- Sarah Thomas answered on 21 Jun 2011:
  
  That’s a really great explanation from Derek, I can’t think of any other way of describing it!
- Tim Millar answered on 21 Jun 2011:
  
  All good answers