Category Archives: amateur astronomy

amateur astronomy, astronomy, astronomy news

Sucker Holes, Media Hype, and Observational Reality

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Be Realistic about Observing

One of the truisms in amateur astronomy is that the minute something exciting is predicted to occur in the sky, the sky immediately clouds up.   This is true especially if there’s an especially juicy coronal mass ejection inciting some space weather in Earth’s close neighborhood.  Or, perhaps an occultation of a star by the Moon. As soon as the news gets out, the clouds start to gather.

This happened to me on October 8th, when the space weather forecast showed a good chance of seeing aurorae even at the mid-latitudes. I mentioned this as part of a talk I gave onboard a cruise ship that day (I do astronomy enrichment presentations for the Smithsonian and Celebrity Cruise Lines) and of course it clouded up that night.  But, we persevered, and eventually a sucker hole did open in the clouds that revealed some of the sky, and we saw a gorgeous greenish display to the north, complete with spiky formations that came and went.

Another case in point has been the media hype for the Orionid Meteor shower that was supposed to deliver dozens or more meteors per hour.  The news media picked up on this right away, and I saw at least one  headline about “spotting a stunning meteor shower” from a news organization that used to have a qualified science writer on its staff but now just rewrites from a press release, spices it up, and then publishes hypey stuff that they think will grab people’s attention. (Yes, CNN, I’m talking about you…)

The press release I got from a reputable observatory mentioned that it might be possible to see up t0 25 meteors per hour.  No promises, just a possibility. No flashy graphics about “dazzling” sights… And, reports I’ve seen from actual observers indicate that the counts have been a bit less than normal.

This is the sort of thing that really ought to give the media a bad name for over-hyping.  A competent science writer would have been able express the story much more clearly for readers/viewers and given a more realistic view of what the shower might look like.

The reality of observational astronomy is that sometimes something can be quite spectacular, and sometimes it just isn’t. Astronomers’ models can only go so far in predicting how good a meteor shower, for example, will look. There are a lot of other factors that influence your observational experience… including clouds.

The best thing to do is get out there and observe… there are some gorgeous skies coming our way over the next few months, so be ready for them! Cherish each meteor, search out the planets, check out the nebulae, and never stop looking for the wonders to be seen in the night-time sky!

 

amateur astronomy, astronomy, astronomy news, impact site, Jupiter

Something Smacked Jupiter… Again

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Is it Rare, or Not?

The June 3 impact of something on Jupiter, courtesy of Anthony Wesley of Broken Hill, Australia, and posted on spaceweather.com

The planet Jupiter got smacked again by an object this past week.  Recall that in 1994, pieces of Comet Shoemaker-Levy 9 blasted their way into the Jovian cloud tops.  At the time, people called it a once-in-a-lifetime event. That is, they did until something else plowed into Jupiter on July 19, 2009.

In an amazing coincidence, a major research paper came out this week, explaining just what it was that impacted Jupiter in 2009.  In another coincidence to THAT coincidence, the same observer who first chronicled the 2009 impact — Australian amateur observer Anthony Wesley — also saw the one that occurred a few days ago.  Christopher Go of the Phillippines captured a video of the event that sent a flash of light out from the Jovian cloud tops. Both are posted at Spaceweather.com, along with frequent updates.

You might be tempted to ask, doesn’t it seem like Jupiter’s getting hit a lot more lately?  The answer is: probably not.  In fact, Jupiter maybe getting less whacked NOW than it was in the past, back when the solar system had a LOT more debris flying around in orbit around the Sun and amongst the planets.  The difference is that we have people watching Jupiter all the time — well-equipped and qualified amateurs — and they’re bound to see these things happening, simply as a consequence of having more people pay attention. And, Jupiter being what it is — massive, strong gravity, and surrounded by debris in various orbits — it’s bound to get whacked pretty frequently.  We just haven’t always had the chance to see it happen.

Think of it this way: if trees fall in the forest on an average of once a day and nobody’s there to see it happening, we could come to the conclusion that trees falling in the forest are rare things. But that would be only because we aren’t looking. It’s an erroneous assumption, of course.  And, once we start putting people in the forest to watch the trees fall, we’d then find out that they’re falling once a day.  But, that doesn’t mean that more trees are falling. It just means we’re watching more. It’s probably the same with Jupiter. We’re watching it more and catching more of these events that could be very commonplace out in the Jovian neighborhood.

Jupiter has a long history of sucking up and sweeping in debris (comets, asteroids, etc.) throughout the life of the solar system.  In the beginning, it probably saved Earth’s skin more than once, by intercepting larger bodies that could have whacked the young Earth and changed it into something that might not be the planet we know and love today.  It’s still picking off debris today, and we’re fortunate enough to now have the technology to see it happen.

Now, about that paper explaining the 2009 collision.  When the impact occurred last year, scientists immediately turned their attention to the aftermath of the collision. They used a whole host of observatories on (and orbiting above) Earth. They mapped the thermal changes in the impact site (in other words, the temperature changes) and searched out spectral evidence of chemical elements that were part of the impactor (that is, they examined the planet in different wavelengths of light to tease out the fingerprints of chemical elements given off during the collision).  It now turns out that the evidence points toward an asteroid plowing into the cloudtops of Jupiter.  Critical examination of the impact debris suggests that the asteroid came from a family of bodies called the Hildas — a secondary asteroid belt that orbits near Jupiter and has about 1,100 members. Hildas are mainly rocky bodies that may also contain some ice.

This past February, when I was out at NASA Jet Propulsion Laboratory for a meeting, I had dinner with an old friend — Padma Yanamandra-Fisher — who was part of the team working on the data analysis of the impact debris. We talked about the event and I asked her if the impact could have been an asteroid. At that time, she was just finishing analysis, but she thought that it sure looked like an asteroid had been the culprit in the collision.

What about the impactor last week?  What’s it made of? It’s too soon to tell. Scientists are busily studying the impact site. There’s not much of an impact cloud to study, but they can take infrared measurements of the zone where the event occurred and get some idea of what the incoming debris could have been.  As with all ongoing science, stay tuned!