Comet Lovejoy was only discovered in late November, but it’s had quite a ride. It was quickly determined to be a Sun-grazer, the kind of comet that plunges down very close to the Sun in its orbit. The date of this solar close encounter: yesterday!
That’s a shot of it using SOHO, a solar observatory orbiting the Sun. The Sun itself is blocked by a mask, and the white circle represents its outline. The comet is obvious enough! The line through the top of it is not real; that’s called blooming and it happens sometimes when a bright object is seen by a digital detector. The electrons in the chip overflow the pixels and leak into adjacent ones. The comet got very bright as it neared the Sun, almost as bright as Venus! This picture, taken on December 15th at 22:36 UT, was shortly before closest approach: a mere 180,000 km (110,000 miles) from the Sun’s searing surface.
Amazingly, after the comet screamed past the Sun, and to the surprise of many, it survived. A lot of comets don’t make it through such an event, but this one did. Here’s a video of the comet reappearing from behind the Sun, as seen by SDO; watch closely or you’ll miss it!
Nifty. But on the way down it had several interesting things happen to it. (more…)
On October 1, a bright comet screamed into the Sun, and apparently disintegrated. This happens pretty often, actually, but in this case, just minutes later, the Sun blew out a pretty hefty coronal mass ejection, a huge explosion of magnetic energy that can release billions of tons of material.
Some people have speculated that these two things are related (including times when this has happened in the past). Are they? We have videos of the event from three different satellites, giving us three angles on what happened, providing clues on what really occurred.
To shed some light on this — haha — I made a short video explaining this, including the footage of the comet collision and CME as seen by the three satellites:
[It helps to set the video resolution to 720p to see the details in the satellite views.]
So my guess is that while it’s possible, it’s not probable. CMEs happen all the time, so I’d expect a few to happen around the same time as comets flying past the Sun just by coincidence. We don’t have any physical reason to think they’re related, and when they are examined more closely, the CMEs usually don’t come from a spot near the Sun where the comet traveled. Still, it’s worth looking into, at least to build up a statistical case on way or the other.
Today, June 21, 2001, at 17:16 UTC (1:16 p.m. Eastern US time), the Sun will reach its peak in its northward travels this year. This moment is the summer solstice — I describe this in detail in an earlier post. Technically, that article is for the winter solstice, but the idea’s the same. Just replace "winter" with "summer" and "December" with "June" and "south" with "north". That should be clear enough. It might be easier just to multiply the entire article by -1. Or stand on your head.
Since for the majority of people on the planet this day marks the start (or more commonly the midpoint) of summer, enjoy the gallery below that shows our nearest star doing what it does best: giving us light, giving us beauty, and sometimes, blowing its top.
Use the thumbnails and arrows to browse, and click on the images to go through to blog posts with more details and descriptions.
Last month, on May 10/11, a bright comet took the Final Plunge, dropping into the Sun. It either broke up and evaporated or actually impacted the Sun, because it wasn’t seen to reappear around the other side. Here’s the video, taken using NASA’s SOHO satellite:
Pretty cool! You can see the Sun erupting with a coronal mass ejection, too. It’s tempting to wonder if the two are related, but in fact the CME let go before the comet had even had a chance to interact with the Sun’s magnetic field (CMEs are essentially magnetic events). I know there are tracts floating around the ‘net about comets causing solar events, but the folks promulgating such ideas never do any actual statistics. They see a comet plunge into the Sun, see a flare or CME, and say they’re related. However, you have to look at how many events happen without comets nearby, and more importantly how many comets hit the Sun and don’t spark an event. Without that, you’re just cherry-picking.
Incidentally, you may have noticed a very short horizontal line going right through the heart of the comet. That’s not real; it’s an artifact of the detector on SOHO. It’s called blooming, and it has nothing to do with Planet X unless you’re willing to turn your back firmly on reality.
Anyway, comets hit the Sun quite often; many have similar orbits and are called Kreutz family comets. It’s funny: many of them get bright enough to technically be seen by the eye, but they’re so close to the Sun they still get washed out.
Actually, now that I think about it, I should mention that SOHO is the greatest comet finder of all time; over 2000 comets have been seen in SOHO images! It seems funny to look to the Sun to find comets, but it’s also amazing to me to think that those 2000 comets have been seen in only 16 years since SOHO’s launch… think about how many comets are out there, in deep space. Millions. Billions. More.
We live in an amazing place, and in an amazing time that we can discover so much about it.
I’ve seen quite a few in my time. Some were faint smudges in a big telescope’s eyepiece, some seen only in distant spacecraft images, and some so bright they were obvious and awesome to my naked eye.
They used to be considered harbingers, omens up for interpretation by mystics and people looking for reasons things happened the way they do. In reality, comets are just a class of objects in our solar system along with planets, asteroids, dust, and one biggish star.
Hmm. Did I say "just"? That’s unfair. They are gorgeous, interesting objects, worthy of study. And 100 years ago today — April 20, 1910 — we got a pretty good look at the most famous of them all, Comet Halley, as it passed the Earth at a distance of just 23 million km (14 million miles). It got so bright that it was obvious even when seen from cities. As geometry would have it, the Earth even passed through the comet’s tail, sparking fears of widespread death (cyanogen was detected in the comet, making people think it would poison them). It was the talk of the planet, featured in magazines and papers across the globe. For your history enjoyment, here is one of those articles from the 1910, transcribed by James Brooks. It gives a great flavor of the times.
To celebrate this remarkable centennial anniversary, I have put together Ten Things You Don’t Know About Comets. I imagine some readers will know some of these, and some will know all ten, but if you do you can still enjoy the pretty pictures — and make sure you click on them to embiggen ‘em. And if you like this, I have several others, too (Ten Things You Don’t Know About… the Earth, Black Holes, Hubble, the Sun, Pluto, and the Milky Way), so check ‘em all out and see how many things you don’t know.
I’ve been posting sporadically on how sunspots are starting to come back to the Sun, and I’m glad to see a new group sprouted up recently… and it’s a monster:
These images are from SOHO, the Solar and Heliospheric Observatory. The orange one is in visible light, and the sunspots are pretty obvious. The green one shows the Sun in the far ultraviolet, and you can see the sunspots are pretty intense, blasting out high-energy light. Sunspots are indicators of magnetic activity, and the intense magnetic field can accelerate plasma (ionized gas) to high energies.
Just so’s you know, a hundred Earths could fit across this image, so that oughta give you an idea of just how big these blemishes are.
What this means is that the Sun is becoming active again. You can see it better in this video I put together using SOHO animations. These are real SOHO observations. Note that some of the data are missing so the Sun’s rotation is a bit jerky, and that you can see that data dropouts and other problems plague these sort of observations. Oh– actually, another group popped up on the Sun earlier, too, and you can see those in the visible light data.
You can actually see the plasma flowing along the magnetic field lines in the latter part of the video.
Right now, the Sun is struggling to climb back up to the peak of its magnetic cycle, which will probably occur in 2013 or later, given how slow this has been — which you might want to keep in mind if some crackpot or scammer is trying to sell you on the idea that solar activity will destroy the Earth in 2012. When the Sun is at its peak, the magnetic field is at its strongest, and we see the most sunspots. However, the strongest solar flares and other explosive events tend not to happen until well after the cycle peaks, so it’ll be late 2013 or 2014 before we see the most vigorous activity, if the Sun holds to its previous behavior.
Again, people selling you on 2012 disasters generally have a very tenuous grasp on science. The less you know the better for them.
I expect we’ll be seeing more and more sunspots now as time goes by. It’s nice to see this happening, as it adds to the activity seen in December, and ends a long period of minimal sunspots — heck, for a long time, there were none at all. Boring. Now we can look forward to some exciting action again… just in time for SDO to launch, too!
[P.S. If anyone can tell me why the first few frames of my uploaded videos turn gray sometimes, that would be nice. I don't know whether to curse iMovie, Flash, YouTube, or all three.]
Phil Plait, the creator of Bad Astronomy, is an astronomer, lecturer, and author. After ten years working on Hubble Space Telescope and six more working on astronomy education, he struck out on his own as a writer. He's written two books, dozens of magazine articles, and 12 bazillion blog articles. He is a skeptic and fights the abuse of science, but his true love is praising the wonders of real science.
The original BA site (with the Moon Hoax debunking, movie reviews, and all that) can be found here.
Contact me: The Bad Astronomer "at" gmail "dot" com
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