Rock Stars!

Planetesimals are the precursors and the building blocks of the current day planets in the solar system. They are akin to the asteroids in the sense that all the cosmic bodies currently in the solar system were formed simultaneously 4.6 billion years ago from a huge cloud of dust and gas known as solar nebula.

Gravitational forces pulled them together ever closer and closer which resulted in the formation of sun at the centre and the planets surrounding the sun. But not all planetesimals eventually wound up as a planet. Jupiter as the largest planet exerted a gravitational pull on many of these celestial bodies once it was formed and these planetesimals were pulled into a stable orbit around Jupiter forming what is now called as the asteroid belt. The asteroids are either the original planetesimals or their fragments.

These asteroids are of three main types:

(1) Chondritic which is made up of clay or rocky material and probably the original planetesimals. Dan Brown’s Deception Point explores this type of asteroid in a nail biting science thriller.

(2) Stony asteroids made of silicate materials and nickel iron. (fragments of other asteroids)

(3) Metallic asteroids from nickle iron usually formed from core of shattered planetesimals.

See what Nina & Nana have to say about planetesimals today.

I’m taking my blog to the next level with Blogchatter’s #MyFriendAlexa

This post is a part of the #NinaAndNana series I co-host with Kanika G.



  1. This is an interesting post Lavanya. Learnt something new from it. My 4 year old would be elated when I read this to him as his current favorite reads are all about solar system.

    Liked by 1 person

      • I have read a few books by Stephen Hawking and watched several documentaries on BBC. But that was long time back when I used to take a lot of interest in Astronomy. But trust you to bring humor into the story by starting off with Astronomy and wind up by bringing Nina and Nana into it. 😃😃

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  2. Interesting article. Never knew this stuff esp. that what we called the big bang theory is called the Solar Nebula. So basically all planets have the same stuff in them and life on another planet may be entirely possible?

    Liked by 1 person

    • Big bang theory is basically about how the universe came into being. Solar nebula is the story of our solar system. But yes, good question, all planets are from the sams building blocks but existence of life is an entirely different matter. For instance, Venus has a surface temperature of above 900c. Life as we know on earth cannot exist there. Mars atmosphere was stripped away billions of years ago and most of the other planet are way too far away from sun and way too cold. But this is what the scientists have been trying to discover for decades now.

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    • Oh, Deception Point was a great read but truth be told there were certain parts where I could second guess the author. But loved the science-mystery combo.

      Liked by 1 person

  3. New terms to show off to my 6yr old! 😉 He loves anything to do with planets.. so thank you Nina & Nana for “spouting arcane facts” and making me do a jig..

    Liked by 1 person

  4. Oh just loved reading it, there was a time when astronomy & space science would give me a thrill, now my son is showing interest in planets and the solar system.

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  5. Aha! I am probably the person who has no clue about these exotic facts, but you know this is something that amuses my 10 yrs, old son a lot, I made him also to read this article. Wonderful facts to learn!

    Liked by 1 person

  6. Oh wow! This is an absolutely new piece of information I learned today – I am fascinated by the night sky but I never really looked into the origination of planets! Thanks!

    Liked by 1 person

    • Thanks Geri, glad you liked it. The Nina and Nana series is primarily aimed at children and their caretakers. There are a lot more in the series covering science, mythology, technology, space tech besides others.

      Liked by 1 person

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