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1) You won't go blind looking at it. Probably.
You've heard this from your mother, your neighbor, and pretty much everyone else: don't look at the Sun or you'll go blind! Well, that's not strictly true. To be clear: no one has ever been permanently and totally blinded by looking at the Sun (despite a recent 30 Rock episode). You can hurt your eyes, but the damage is usually not total, and a lot of it heals (though not always completely).
Usually, damage to the eyes from looking at the Sun happens during a total solar eclipse. The eclipse itself doesn't hurt you -- after all, the point of the eclipse is that the Sun is covered by the Moon! -- but the damage happens in the moments right after the eclipse. While the Sun is blocked, your pupil dilates to let in more light, so when the first sliver of the brilliant Sun reappears your eye is flooded with light. This can cause damage to your retina called solar retinopathy. It's actually not heat damage, but photochemical; the flood of UV light actually alters the chemistry of your cells, damaging them.
In general, the damage is minor and can heal well, though there can be some permanent though relatively minor effects (in other words, you still shouldn't stare at the Sun). Usually the damage is worse in children because their lenses let in more blue light (the lens yellows with age, acting as a natural filter for UV light).
So you won't go permanently and totally blind from looking at the Sun... unless you do it looking through binoculars or a telescope. But then in those cases there are Darwin Awards to consider.
Incidentally, using sunglasses to look at the Sun can actually make things worse, since they block visible light and your pupil dilates to compensate. If you want to observe the Sun -- and I recommend it, because it's fascinating and utterly beautiful -- then read Mr Eclipse's guide to safe solar viewing. It's a site for sore eyes.
March 3rd, 2009 at 6:29 am
Nice green flash. I knew all of these (more or less), but I want to add #11, which I think is cool: We’re all made of sun. Maybe not our sun, but sun nonetheless.
March 3rd, 2009 at 6:39 am
Nice one Phil, you simply never disappoint. I knew 9 out of those 10. BTW, another one like that about Sirius, is to ask what is the closest star. That usually ends up even worse because, unlike α CMa, most people heard of the Centauri system stars…
March 3rd, 2009 at 6:40 am
Excellent, as usual, Dr. Plait!
Re: Neutrinos, The missing neutrino puzzle was the basis for my favorite Arthur C Clarke novel, “The Songs Of Distant Earth”… I’m glad it was solved in a way that DIDN’T involve the sun going nova…
This article really makes me want to invest in a solar telescope. You are right: we do take the sun for granted. Backyard astronomers like me spend hours squinting at stars dozens of LYs away, while a perfectly fascinating star is only 8 minutes away (as the photon flies)! I shall endeavor to pay our sun more attention in the future…
March 3rd, 2009 at 6:42 am
Amazing Phil! Simply Amazing! Keep it coming…
March 3rd, 2009 at 6:42 am
This is the sort of entry that makes this site invaluable.
Not that the other ones are not entertaining and informative, but generally, they’re more topical and not entries one captures to teach youngsters about their local neighborhood in the Universe.
Very well done, Phil and thank you.
March 3rd, 2009 at 6:42 am
All that, just 150 million kilometers (93 million miles) away.
Sleep tight.
I will, with eight thousand miles of (mostly molten) rock blocking me from it while I’m asleep.
March 3rd, 2009 at 6:45 am
Oh, and #5 is partially explained by our friend Rayleigh. He was a bit scattered, but he loved the blues and Coldplay’s “Yellow.”
March 3rd, 2009 at 6:53 am
But… the Sun being white… Isn’t it the other way around? It’s some millions years we are used to that light, our eyes got optimized for it. There was, according to Darwin, a kind of ape that saw the Sun green, but got extincted with the first traffic lights
March 3rd, 2009 at 7:00 am
Dr. Phil Plait: “… there’s a lot about the Sun that’s still not understand.”
Posted at 6:00 a.m.! Are you up early or up late, Phil?
I think that you’re up late, that should be “understood”, not “understand”.
March 3rd, 2009 at 7:02 am
You forgot to mention the current utter lack of sunspots. That and the fact that the predictions for the next solar maximum keep getting pushed back a few months at a time. These are important facts for the coming decades and ones that prove we don’t know as much as we think we do about that giant ball of fire.
March 3rd, 2009 at 7:09 am
Cough cough. I must laugh.
10 things i don’t know about the sun? More like 1 thing; I only didn’t know number 8. And I’m only 15 years old…
March 3rd, 2009 at 7:17 am
#6 is just a lovely example of how science works properly. Prediction, experiment, problem with results, new prediction, new experiment etc etc
None of this “I give up, we puny humans are too stupid to do this, let’s just say god did it and go home” rubbish.
March 3rd, 2009 at 7:19 am
I love the “Ten Things…” series. Keep them up, Phil.
March 3rd, 2009 at 7:22 am
Sleep tight??
And to think I lost sleep this week thinking about how much I’ve lost on the stock market! Great post, Phil.
March 3rd, 2009 at 7:30 am
Hey Phil,
I want to see this on your Facebook page as one of those “X Random Things You Should Know” notes.
March 3rd, 2009 at 7:36 am
You’ve outdone yourself with this post Phil
Fantastic read, thank you.
March 3rd, 2009 at 7:42 am
I knew that massive stars are relatively rare, yet I had bought into the “Sun is below average” idea. It’s always interesting to discover a little bit of cognitive dissonance going on.
March 3rd, 2009 at 7:45 am
OK, so the Sun is pretty bright. Ever wonder why?
Genetics? Raised in a nurturing household?
March 3rd, 2009 at 7:55 am
That looks like it was quite a bit of work to write.
March 3rd, 2009 at 7:55 am
When I was a kid, I used to look at the Sun quite often through my telescope.
Of course, I had a solar filter on the lens, through which you could only see the Sun and the filament of a light bulb.
March 3rd, 2009 at 8:14 am
I’d say that the Sun defines “white” for us, since our eyes evolved to match its spectrum. And the mid-day Sun has always looked white to me, when I’ve dared to glance at it. I guess I tend to think of the “yellow” Sun as being like the iconographic heart shape that’s shaped nothing like a heart.
Re: the Sun’s averageness, one way to look at it might be: given a random hydrogen atom, how likely would it be that it would be found in a star of about the Sun’s mass? (Or: how many would be found in stars of lesser mass, vs. how many in stars of greater mass?) I don’t know the answer, but I wonder if framing it that way would make the Sun seem more average.
March 3rd, 2009 at 8:16 am
Not that it would matter much, since all life on the Earth would die pretty quickly without the Sun nearby. (Unless you took the Earth with you when you plopped the Sun down elsewhere, in which case it would still be quite visible during the day.)
March 3rd, 2009 at 8:19 am
Hang on, let’s be clear about the fusion business – one often hears E=mc^2 being invoked to explain how fusion produces so much energy, but really it has no more relevance to fusion than it does to any normal form of burning. The tremendous amount of energy released in nuclear fusion stems from the strength of the strong nuclear force, not because matter is being converted into energy (a la matter/anti-matter annihilation). It can be quite misleading as well; I recently read an article massively over-estimating the potential energy yield from fusion, by assuming that all of the mass would be converted to energy.
March 3rd, 2009 at 8:27 am
When I use that old, “What’s the brightest star?” line to new friends and acquaintances (old friends and acquaintances having long since learned to avoid me), I will invariably get at least one wiseacre who responds, Eta Carinae. Now how this person knows that bit of astronomical trivia (probably saw it on the bottom of a Snapple bottle cap) is beyond me, but the fact they can pull it from memory pretty much ruins the whole set-up.
Now I have to be careful to say, “Which star is apparently the brightest as seen from Earth?” which just doesn’t have that zing to it.
March 3rd, 2009 at 8:30 am
Phil,
Your Kansas lyrics made me think of Joni Mitchell at woodstock. She sang that we are all made of atoms from long dead stars:
“We are stardust
Billion year old carbon
We are golden
Caught in the devil’s bargain
And we’ve got to get ourselves
back to the garden”
March 3rd, 2009 at 8:34 am
Isn’t the Sun’s yellowness explained because its white light has the short-wavelength (blue) components Rayleigh scattered by particles in the atmosphere, leaving more yellowy-white?
March 3rd, 2009 at 8:43 am
Dr. Phil Plait:
Err… Phil, how did you arrive at that figure? The speed of light in a vacuum is exactly 299,792,458 metres per second (due to the definition of the metre). So, c2 is ~8.99×1016.
P.S. Yep, I’m keeping track!
March 3rd, 2009 at 8:48 am
“Sirius is the brightest star in the night sky.”
If the Sun was a lot farther away, it would be night…
March 3rd, 2009 at 8:52 am
Such great descriptions. Succinct without being dry. This really is your forte, Phil.
Yet, I’m still going to tell my kids they’ll go blind looking at the sun. I correct this when I have confidence they won’t aim for winning a Darwin award.
March 3rd, 2009 at 9:08 am
So what color would Raleigh Scattering make, say, Betelgeuse look like on a terrestrial planet? Still red?
Just interested because I used Betelgeuse and Rigel the other night to show my nephew that stars do indeed have colors.
March 3rd, 2009 at 9:14 am
“I’d say that the Sun defines “white” for us, since our eyes evolved to match its spectrum.” That’s what I was thinking, but Nemo beat me to it.
Actually I’ve always been baffled by the statement that the sun is yellow- it’s never appeared yellow to me- typically it appears red to me, then picks up a reddish hue near the horizon- but it has never appeared yellow to me.
March 3rd, 2009 at 9:25 am
Jeff, both explanations are perfectly valid. Also, since the fusing nuclei are quark-gluon plasmas it is not at all obvious that the mass difference cannot be attributed at least in part to net matter-antimatter (in this case gluon-antigluon) annihilation.
Great essay, Phil. There were quite a few bits that I didn’t know.
March 3rd, 2009 at 9:27 am
Great article! I guess that the sun is a natural object to worship if you just have to worship something. It makes everything we are and do possible. It is always present and we can feel and see the effects daily. It is effectively omnipotent and will last forever as far as we will know anything about it. Most importantly, it marks our place in the universe. As someone said, if you are observing the solar system from Outside, our little neighborhood is just the sun, Jupiter, and some junk. So much for the geocentric view of the world.
March 3rd, 2009 at 9:31 am
Yay science!
March 3rd, 2009 at 9:34 am
“Yes, we KNOW about evolution. Deal with it”!
Heh! Good one, Phil!
RE: Your tidy bedroom in the background of that video in part 3 of your post.
My bedroom looks like Nagasaki after “The Bomb” was dropped!
March 3rd, 2009 at 9:35 am
6.3 billion years?
Some say 4.5 to 5 billion.
March 3rd, 2009 at 9:37 am
P.S.
I know all those things about it!
March 3rd, 2009 at 9:43 am
Brian Schlosser, “as the photon flies” that would be zero minutes!
March 3rd, 2009 at 9:48 am
Quick! What’s the brightest star in the sky?
ME!
sing with me!
That is why all the girls in town
Follow me all around.
Just like you, they long to be
Close to ME.
– The Carpenters (paraphrased)
March 3rd, 2009 at 9:48 am
Brilliant! Once again, I’ve learned several new things and had fun doing so! Dr. Phil, why don’t you have your own TV series? I’m thinking a continuation of where Sagan left off: The New Cosmos with Dr. Phil Plait. Or something more original: Dr. Phil Plait Just Blew My Frakking Mind, Man would be great with the 2 AM stoner crowd.
March 3rd, 2009 at 9:51 am
Hi BA,
Interesting article. However I am surprised that you admit that you did not know some of them before you wrote your book. All of those you mentioned I cover in my Astro 101 introductory astronomy class!
Cheers
Ozprof
March 3rd, 2009 at 10:18 am
Dr. Phil Plait:
Actually, it was Sir Arthur Eddington who first proposed the idea that the pressures and temperatures at the core of the Sun could produce a nuclear fusion reaction that merged hydrogen (protons) into helium nuclei, resulting in a production of energy from the net change in mass. The preponderance of hydrogen in the Sun was confirmed in 1925 by Cecilia Payne. The theoretical concept of fusion was developed in the 1930s by the astrophysicists Subrahmanyan Chandrasekhar and Hans Bethe. Hans Bethe calculated the details of the two main energy-producing nuclear reactions that power the Sun.
March 3rd, 2009 at 10:38 am
That being said, this list (which is excellent!) would be a *great* addition to any Astro 101 course.
March 3rd, 2009 at 10:47 am
I still don’t get the color thing. What happens when you make a pinhole camera and project the sun on a white background? I see a yellow circle. Is that just me? If I shine a white light flashlight on the same white background, I just see a brighter white.
March 3rd, 2009 at 10:51 am
Another “Things that will make you go blind” myth busted!
March 3rd, 2009 at 10:52 am
thank you.
just marvelous.
March 3rd, 2009 at 10:55 am
God said, “Let there be light.” And the Sun was.
March 3rd, 2009 at 11:13 am
@Jeff:
According to my astronomy 101 book, some mass is actually converted to energy during hydrogen fusion. The short version is hydrogen fusion take 4 hydrogen atoms and turns it into a helium atom. That’s 4 protons into 2 protons and 2 neutrons. A neutron has less mass than a proton. Where does that extra mass go? Gamma rays, positrons, and neutrinos. The gamma rays get bounced around in the sun, being absorbed and re-emitted, until they reach us at various wavelengths.
The long version appears much more complicated than that, but in short, yes, matter does get converted to energy.
March 3rd, 2009 at 11:13 am
The next/previous thing is annoying and a cheap way to increase page views.
March 3rd, 2009 at 11:18 am
For some reason, I expected to see Phil pop the four (He) mini-marshmallows into his mouth and ‘burp’, explaining: “gas”.
|(
[off topic]
Two things you may not have known about Brian Cox:
He hosted a show recently run on the Science Channel: What Time Is It? about the nature of Time (Space/Time) (also, I don’t see any upcoming repeats of it in the immediate future)
He will appear on the second episode of the upcoming NBC series KINGS – see link to SciFi Wire, with the mention at the end of the article
http://scifiwire.com/2009/03/ian-mcshane-goes-from-foul-mouthed-barkeep-to-one-of-nbcs-kings.php
[/back on topic]
J/P=?
March 13th, 2009 at 4:00 am
[...] <Back to Ten Things You Don’t Know About Pluto main page> [...]
March 18th, 2009 at 9:52 pm
Hello, Mr. Plait, I was viewing your video on page 4 about the density of the center of the sun, and while watching out of the corner of my eye at exactly 1:40 I noticed a kind of ‘ghostly’ object fly behind you. It appears to whip through the air in a downward, slanted motion.
Of course, this maybe nothing but just a blip on the video or whatever, but recently I have been listening to Coast to Coast AM and Mr. Noory had a guest who spoke about ‘unseen’ objects recorded on video…mostly of what they call ’shadow people’.
By the way, love the blog. Peace.
March 18th, 2009 at 10:24 pm
I just looked, and I think it’s a dust mote right in front of the camera, so it’s out of focus.
May 14th, 2009 at 3:20 am
[...] for them, it is unlikely the damage is permanent, since looking at the sun rarely makes a person permanently [...]
June 22nd, 2009 at 9:12 am
[...] Things You Don’t Know About the Sun. What I do know is that I haven’t seen enough of it this winter. * Modern Technologies That [...]
January 25th, 2010 at 3:49 pm
I learned so many different things about the Sun!!! I hope they put more things up!!