Mercury passing in front of the sun

May 8, 2003 on 6:36 pm | In Ad Rem | 3 Comments

Today’s APOD is a great example of how various objects in the solar system scale to one another. Most everyone has seen the elementary school planetary models of foam balls. To get such a model to scale would not be possible, so you must of course suspend your disbelief. How large is our star really? This shows Mercury passing in front of the sun. It may be hard to spot Mercury, it is the tiny dot. Mercury is that small in comparison to the sun, even at a distance of almost 58 million kilometers. Sunspots are another great way to determine that a star is unbelievably large. Here you can see a sunspot over 30 times the diameter of the earth and it appears as a spec on the surface of our local star.