
You have questions related to planets and solar system….and then someone from ISRO (Indian Space Research Organization) answers them! It doesn’t happen everyday! But it happened with our little inquisitive geniuses.
Our kids from IIIrd standard had some questions and Mr. Subramaniya Athireyafrom ISRO answered them. Here are the questions:
1) Jupiter is the big planet in the solar system but why it has shortest day?
2) Why all planets are round? Why they not in other shapes? Is there any scientific reason?
Mr. Subramaniya Athiray was patient and kind enough to broaden the knowledge-periphery of the kids with detailed answers. Here are the answers:
1) Jupiter is the big planet in the solar system but why it has shortest day?
Well ! very difficult question as so far we don’t have any clear theory which gives the best reasoning for this observation. However, with my understanding it could be due to the following.
The entire solar system formed from a big ball of rotating gas. first the sun formed from the hot gas first. as you go away from sun heat will be reduced (similar to moving near and far from a candle). Jupiter, the biggest planet in our system formed from the rotating gas which were there at far off distance from the Sun. Rotating objects has a property called Angular Momentum. The cool gas from which Jupiter was formed was rotating. Once the planet start to form its mass increases. Mass increases means gravity increases ie., it gets more and more material and push it towards center similar to cycle pump. When will it stop pushing (answer for that is next question of why planets are round). Now compare this with ICE SKATING – please explain them what is ice skating. when they dance in that keeping hands streched they have normal rotation. but once they bring their hands towards their chest they rotate faster and faster… In a similar fashion, jupiter started to form with a rotating gas.once gravity started to play more and more rotating gas were accumulated and pushed inside (ie., coming closer and closer .. similar to bringing hands towards the chest). as a consequence, rotation increases.
But to my knowledge still we don’t have a theory to explain why jupiter rotate faster. This is what i could think of and read and understood.
2) Why planets are round?
The reason is GRAVITY. Planets as i told they form from dust and gas. once mass of the system starts to rise, gravity will try to bring more stuff which will be pushed towards the centre. this means the whole mass is acting or going towards the Centre that is how gravity will act. Imagine a cycle pump how it pushes and pushes. gravity pushes all the mass towards the centre. Now if it starts to get more and more and more and pushes everything to centre its mass will go on increasing increasing and finally it nothing should be there as all of them will be pushed towards the central point. But we still see planets today !! how come?? when will they stop pushing ??
Take the cycle pump example, if you keep on pushing the air in the pump to the tube, after sometime touch the bottom of the pump, you will feel the heat. Wow! so temperature will be increasing when you push towards the centre and material will start to give a force against the gravity. Now take the tug of war game. each side people will be pulling the rope. which side gives more force, they will pull the rope and all people will come in that side., similarly a competition between the gravity which is a force acting towards the centre and balancing force from centre towards outside (say heat, radiation or material rigidity etc). simply there is a force from inside balancing gravity. hence it is not shrinking any more. Gravity acts equally on all mass and push it to centre and hence it becomes a round shape.
Say for example, asteroids are not of round shape they are very weird in shapes, because they are not very massive and hence low gravity which is not sufficient to make them round.
Students of Class III thank him in their own way:)