Origin of planet earth

QuestionEdit

QUESTION: I heard something within the last year, probably on NPR, regarding the origin of our planet and the series of astonishing occurances that had to have transpired for the planet to have been created and then survived (bombardment from other moving bodies, etc). The description suggested it could be possible there is not another planet out there like ours. The explanation was quite thrilling. I would like to be able to find that explanation somewhere on the internet, or would like someone to repeat it to me. I'm sorry I can't better explain my quiry. I'm not a scientist but am an avid listener to Science Friday. I emailed Ira Flatow, but received on response. I thank you for your time and expertise.

This is not a homework assignment - I'm 67 years old.

ANSWER: Hello,

The assertion that the Earth is somehow unique and couldn't survive "bombardment" by other bodies simply doesn't fly or hold water. We already have documented more than 150 extra-solar planets (associated with other solar systems) so it appears the dynamical basis for planet formation is pretty well established empirically. Planets - even some Earth-sized, CAN form relatively easily and are not scarce even in our local cosmic neighborhood.

This also puts the kibosh on the notion there can't be another planet out there like ours. Or roughly like it, at least which can accommodate some form of life. If there are already so many extrasolar planets that exist, there may easily be some percentage that have life - or more to be found which might.

So no "explanation" is needed. The premise of the claim is simply a bad one. Also, it kind of resembles that for the "anthropic principle" (which you can google) in terms of humanity and its planet exercising some kind of uniqueness in the cosmos.

An excellent demolition of this argument can be found in the late Carl Sagan's book: 'The Varieties of Scientific Experience', Penguin Books, pp. 55-61. Therein, Sagan brilliantly lays out the faulty reasoning and how it is actually derivative of the antiquated thinking responsible for holding on to the geocentric (Earth-centered) view of the solar system for so long. (In fact, the relevant chapter is entitled, 'The Retreat from Copernicus')

Hopefully this helps. Seems like NPR is trying to assuage some viewers' religious instincts! (Or perhaps they believe they are creating and broadcasting more "balanced" content!)

---------- FOLLOW-UP ----------

QUESTION: I want to emphasize that it might not have been NPR. I also want to emphasize I am not religious - in fact, one might say I am anti-religious. Nor am I anthropocentric. I don't feel that man is anything more than just another animal. The description I related to you was strictly science - describing a sequence of events that occurred (e.g., protection by the planet Jupiter?), resulting in a planet that could later sustain life. It was just science - that's why I found it to be so elegant. I guess I'll never find it. Perhaps I was dreaming.

Thank you again for your time and expertise.

AnswerEdit

Hello, again:

you wrote:

"I want to emphasize that it might not have been NPR. "

Okay, fair enough. That might make more sense. If you can locate or identify the source that would be good.

"I also want to emphasize I am not religious - in fact, one might say I am anti-religious. Nor am I anthropocentric. "

I **never** meant to imply **you** were - either of those. I only intended to show that the "exceptional" or uniqueness (origin of Earth) arguments, claims are typically found amongst religious believers - particularly of the ID (intelligent design) crowd. They have also (lately) jumped on the anthropic principle bandwagon to try to give their case more - how should I say - "scientific window dressing"

Note here, YOU did not make any such claims or arguments - you merely *related to me* a source that did. That does not make you religious or anthropocentric!

"I don't feel that man is anything more than just another animal."

Good, and this is a rational stance to take until any teleological claimant can demonstrate the validity for a "soul". Or afterlife.

"The description I related to you was strictly science - describing a sequence of events that occurred (e.g., protection by the planet Jupiter?), resulting in a planet that could later sustain life."

I am not so sure I'd go so far as to say it was "just science. It was more *scientific speculation* based on certain assumptions. "Protection by Jupiter" - like some "big brother" - is a claim or assertion that would have to be proven. It also bears the unscientific veneer of what we call teleology - or imputed purpose. I.e. Jupiter's role is the "protection" of Earth. Science - true science, never adopts or validates teleology. Particularly in terms of "helping Earth to sustain life".

All such claims would have to be rigorously and seriously demonstrated - not just made or said based on some circumstantial evidence. I have seen nothing anywhere, in any journals, to warrant that.

"It was just science - that's why I found it to be so elegant. I guess I'll never find it. Perhaps I was dreaming."

Again, I dispute it was science. It comes over as hyper-scientific speculation, which alas, there is way too much of nowadays. From using wormholes to travel through time, to all this 2012 Mayan nonsense that so many seem to be going bananas over. (And now a movie about it coming out in December, as if all the other hype weren't enough)

No one says you were "dreaming" - BUT, if you can locate the source, it might explain a lot. Including whether there is some ulterior agenda at work.