Witness History: As MESSENGER Speeds by the Planet, See Mercury Before Sunrise! September 29 to October 1, 2009

 Posted by DrJeff on September 28th, 2009

 Copyright 2009  |  About this blog


Mercury Sky
This post is a Teachable Moment in the News.


Given the BotU Special Post for the MESSENGER Flyby, I thought this would be a great supplemental post.


Some Cool Background

Imagine you’re looking at a bug flying around an outdoor light bulb at night. Let’s say you’re looking at it from a distance which is always greater than the distance the bug is from the bulb. Wow. It’s a really interesting bug you’ve never seen before, and you want to share the experience with a friend, or (in my case) your son or daughter. I might say “Hey Jordi! Check out this really cool bug!” He’d say, “Daddy, where??” Ok, now I’ve got to tell him where to look. What would you say? How about: “over there, near that light bulb.”


Well this is EXACTLY the situation with the planet Mercury for earthbound observers. Mercury is orbiting the Sun and we’re looking at it from Earth, which is at a greater distance from the Sun than Mercury is from the Sun.


So if you want to see Mercury in your sky, you need to look … near the Sun. Anybody see a problem with that? The Sun is a pretty high wattage light bulb, and if it’s up in the sky, you’re not going to see Mercury or the stars for that matter. They’re up there with the Sun but their light is absolutely swamped by the sunlight illuminating our atmosphere.


Just so you know, the Sun light bulb is General Electric model #big01bertha, and its wattage is 383,900,000,000,000,000,000,000,000 Watts. It is also guaranteed for another nearly 5 billion years of operation. Handle with care.


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The Milky Way: Our City of Stars

 Posted by DrJeff on August 10th, 2009

 Copyright 2009  |  About this blog


HST Sag Final2

This post is a Dr. Jeff’s Jeffism.


First a word from our Sponsor—

Come back Thursday August 13, for my take on the White House blue-ribbon panel looking at the future of NASA’s human space flight program.

Come back Monday, August 17, Rod Serling will be posting here on BotU: “Weekly Challenge 6: Today’s Special in the Cosmic Kitchen is …”



There’s no sight like the sky on a cloudless night far from city lights. The heavens filled with seemingly countless stars is overwhelming. At those moments, I cannot help but wonder if on a planet orbiting that star over there might be someone also looking heavenward, and in their sky is our Sun as one star among many. It touches the depths of one’s soul to look up into the night sky and wonder who might be staring back.


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