Killer Solar Flares and Rogue Comets, Oh My

They Aren’t Going to Be Harming Us

Earth is NOT doomed. Yeah, I know this is going to come as a complete disappointment to the folks who insist the universe is out to get us via the auspices of giant killer solar flares and rogue comets. It ain’t gonna happen. Lucky for all of us, the universe is sticking to the laws of physics.

The Valentine's Day 2011 solar flare. Courtesy NASA/SDO/SOHO

Let’s start with the so-called giant killer solar flares. Yes, increased solar activity, including flares and coronal mass ejections (outbursts from the Sun), is a concern. This is because we’re heading into a period of maximum solar activity (something the Sun goes through periodically), and we are expecting more solar flares and coronal mass ejections.

This is pretty much normal for the Sun, despite some of the screaming headlines on conspiracy theory Web sites about “mysterious” solar flares and what they supposedly mean for mankind.

In reality, solar activity is not mysterious. It’s not confusing scientists, nor is it being directed by aliens (yes, I saw that on a Web site). Solar activity is part of what our star does.  Solar physicists (the experts on solar activity) are really starting to understand some of the mechanisms of solar flares, for example, thanks to solar-observing satellites such as SDO, STEREO, and SOHO.  But, giant killer solar flares? Those are a product of overworked imaginations of people who don’t understand the basic principles of physics and the Sun.  For one thing, there isn’t enough energy in the Sun to power a monster fireball that could hang together long enough to travel 150 million kilometers between the Sun and Earth.

Sure, solar flares can be strong enough to create space weather disturbances that can stimulate auroral displays above our poles. All that means is that the energy transfer from Sun to Earth is strong enough to excite gases in our upper atmosphere, which causes them to glow. This happens a lot, and not just on Earth. Aurorae have been seen on such planets as Jupiter and Saturn, for example. Same principle at work there, too.

In some cases, the space weather can mess a bit more with our upper atmosphere, which affects some of our technology—such as telecommunications and GPS signals. (For more information about space weather, visit the Space Weather FX Web site at MIT. It contains a series of very nicely produced videos (if I do say so myself) about the effects of space weather. Very timely and very educational.) Studying solar flares is an important step in understanding the whole Sun and the cycles it goes through, and I, for one, look forward to seeing what astronomers learn about our star during this next solar cycle.

The other great story that’s been making the rounds among the “we’re gonna die” crowd is about Comet Elenin. It is (or was, actually) a perfectly harmless comet making a swing past the Sun (as many comets do). A few folks got all hot and bothered by their own misconceptions about the comet’s orbit and they worried that all kinds of disasters would occur on or to Earth, all caused by the comet. I read some of these…ummm… pseudo-scientific rants. To be honest, I never could figure out what the fuss was about. And some of the uneducated hyperbole was… laughable.

Comet Elenin as seen by HI1-B on Aug. 6, 2011. As Comet Elenin passed to within just 7 million kilometers of the STEREO (Behind) spacecraft, NASA rolled the spacecraft to take a look at it (Aug. 1, 2011) with its wide angle HI-2 instrument. Though the observation lasted only a little over an hour, the fuzzy looking comet can be seen moving across a small portion of the sky. STEREO will be taking these one-hour observations every day through August 12. The comet is seen by the HI-2 telescope between August 1-5, and by the higher resolution HI-1 telescope between August 6-12. From August 15 onward, the comet enters the HI-1 telescope's nominal field of view, at which time we should enjoy continuous viewing of the comet. Over time, we expect the comet to be visible in the SOHO C3 coronagraph on September 23 for six days and possibly STEREO's COR2 coronagraph as well between August 20 and September 1. Courtesy NASA/STEREO mission.

As it turns out, there never was anything to be worried about. Comet Elenin came as close as 72 million kilometers to the Sun and never got closer than about 34 million kilometers to Earth. For reference, the Sun and Earth are 150 million kilometers apart; Venus and Earth are close as about 38 million kilometers apart when they are closest to each other in their orbits. So, Elenin was never in any danger of smacking into us.  It faced far more danger from its close approach to the Sun.

As it passed near the Sun, Elenin broke up into a traveling collection of ice chunks and bits of dust. It’s now scattered along its former orbit.  According to Don Yeomans, the comet expert at the Near-Earth Objects Program Office at Jet Propulsion Lab in California, about two percent of new comets passing by the Sun break up like this. This is because most comets are made up of ice, rock, dust and other stuff that are all held together in a loosely bound conglomeration that can be easily disturbed by the pull of gravity from a nearby planet or the Sun. This is all perfectly natural and nothing to be worried about.And, trust me, comets can’t screw with Earth’s axis or change our magnetic fields or do any of the stuff that they’ve been accused of by some of these pseudo-scientists.

Look, the solar system is an interesting place scientifically. We continue to explore it and learn more about it. Everything we learn is from observations and the applications of basic scientific laws. The more we look, the more we discover, quite simply because we keep creating better and better tools with which to study the cosmos. This is great, and it’s what science is all about: figuring stuff out from the evidence in front of us, using scientific principles to do so.

Science doesn’t make the solar system weird or mysterious or frightening or alien. People with a vested interest in having you believe (and the operative word here is “believe”) their untested, unscientific assumptions about things they don’t quite seem to understand may drive a few folks to read ranting Web sites. I’m sure it feeds the egos of those people who have books to sell or tales to tell. But, it’s really not the way that sane, rational people view the cosmos. And, it’s certainly not the way science works.  The universe is grand and wonderful enough without making up inane stuff about it.