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All posts for the month August, 2010

But Not Goodbye

Last week an old friend and colleague, Jack Horkheimer, passed away. To most of the world, Jack was known as the Star Gazer (formerly the Star Hustler), for his little five-minute astronomy video short shows that aired on PBS for years and years.  For many of us in the planetarium profession, Jack was a long-time colleague and director of the Miami Space Transit Planetarium. I’d known Jack since the early 1980s, when we met at a planetarium conference in Memphis, Tennessee. I remember we sat at a coffee shop, a bunch of us, swapping tall tales and telling jokes, and Jack had some of the funniest stories to tell about giving shows at his planetarium. I didn’t see Jack again until 1986, when we were all at a Voyager 2 flyby press event at JPL. He’d been popular as the Star Hustler for some years by then and he was at JPL to gather fodder for his shows and talks. I remember going out to a bar with Jack and another couple of his friends during that busy week, and again, we swapped tall tales and jokes.

The Jack Horkheimer I knew as a planetarian was quite a guy — maybe not always as swaggering as his Star Hustler (later renamed “Star Gazer”) persona, but always personable and friendly.  He was a thoughtful guy, ready to help folks out when they needed it, and always up for sharing astronomy with anybody. His ideas about astronomy being for everybody inspired a number of us as we sought our own paths to sharing astronomy with the public.  He was a public fixture and a planetarian to the core.

It was with great sadness that I heard of Jack’s death.  He had moved to Miami many years ago, as he put it, to die from a respiratory ailment he’d had.  The climate must have agreed with him, because he not only didn’t die — he thrived. In the end, his ailment took him away, but not before he brought astronomy to a wide audience.  The world is poorer for his loss, but you know what? We’re all richer for having had him there all those years to point out the stars and bring the skies to everyone with his engaging Star Gazer series.  RIP, Jack — and we’re all looking up!

It’s Nonsense

How Mars and Venus will look after sunset on September 27. Does Mars look as big as the full Moon to you?

So, by now, you’ve probably heard that Mars is going to look as big as the full Moon tonight. It’s a very popular Internet meme these days, sent around by people who think it sounds cool but never stop to think about the physical situation that such a story represents.

Epic fail on their part. Don’t let it be one on yours.

Think about it. How far away is the Moon?  I’ll tell you — it’s (on average, depending on where it is in its orbit) about 384,000 kilometers away from us.

Now, how far away is Mars?  I’ll tell you that, too.  When Mars and Earth are at their closest points in their orbits, Mars can be about 55 or 56 million kilometers away.  That makes it look like a reddish point of light from our vantage point here on Earth.

Okay, now compare 384,000 with 55 million.  BIG difference.  It’s a big enough difference that Mars will always, always, always appear as a point of light in our sky.  And the Moon will be brighter and bigger and look like… the Moon.

If Mars were to look as big as the full Moon in our skies, we would have BIG problems. Bigger than worrying about how it would look in our sky. Let me put it to you this way: if it were as big as the full Moon in our sky, we’d be looking for a way off-planet before the tidal forces broke both worlds apart. NASA explains it all pretty well here.

So, don’t believe the meme — don’t let some foolish person’s misunderstanding of science and planetary orbital mechanics live rent-free in your brain.

Instead, head out tonight and check out Mars and Venus after sunset. They look lovely, without all the need for breathless Internet/Web hype.