Significance?

In astronomy, the typical way to give the mass of a large object is in solar masses, denoted M. This isn’t an exact measure, but it’s good to a suitable degree of accuracy. For example, Sirius A is about 2.02 M. Betelgeuse and Rigel both weigh in at around 18 M. So, here’s a question. Including all of the planets, how much do you suppose our entire solar system would weigh?

1.0014 M. That’s all. Our entire solar system is basically just the Sun. Plus a dusting of leftover crumbs from when it was forming. All of the planets combined make just 0.14% of the mass of the Sun. On this scale, planet Earth barely even registers.

And if that doesn’t challenge our imagined self-importance or the delusion that we have some privileged position in the Universe, then I don’t know what will!

About Invader Xan

Molecular astrophysicist, usually found writing frenziedly, staring at the sky, or drinking mojitos.
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3 Responses to Significance?

  1. Prof. Bleen says:

    Does that include all the Kuiper belt objects?

    • invaderxan says:

      I believe so, yes. At least, assuming there isn’t some hitherto unknown lurking behemoth. It’s the estimated total mass of the system.

      (Though I’m not sure whether this estimate assumes an Oort cloud or not…)

      • Prof. Bleen says:

        Okay—thanks. I thought of the Oort cloud after I posted the comment.

        Wikipedia says that the total mass of all Kuiper belt objects is probably less than 0.1 Earths, which of course wouldn’t change the total mass at four decimal places.

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