By Phil Plait | September 21, 2012 9:32 am

According to my software, this blog post you are reading is the 7000th article I have published on the Bad Astronomy Blog.


That’s a lot of words. It’s also a lot of astronomy, geekery, science, antiscience, web comics, puns, embiggenates, and "Holy Haleakala!"s (61, to be exact, plus this one to make 62).

I am generally not one to wade into maudlin celebrations of arbitrary numbers, so instead I’ll celebrate this milestone by showing you something appropriate: the North America Nebula, taken by Mexican astronomer CĂ©sar CantĂș.

[Click to encontinentenate.]

Why is this appropriate? Because the New General Catalog of astronomical objects – familiar to and used by astronomers across the planet – lists it as entry number 7000.

And it should be obvious why it’s named as it is.

Of course, I can’t leave you with just a pretty picture. This nebula is something of a mystery; we don’t know how big it is or how far away it lies. In the sky, it’s very near the star Deneb – which marks the tail of the swan constellation Cygnus – and Deneb is a massive, hot, and luminous star. It’s possible the gas in the nebula is glowing due to the light from Deneb; if so NGC 7000 is about 1800 light years away and over 100 light years across.

It’s the site of furious star formation, too, with stars being born all along the bright sharp region which look like Mexico and Central America. The "Gulf of Mexico" region – the darker area with fewer stars – is actually the location of thick interstellar dust that blocks the light from the stars behind it. Visible light, that is; the dust glow in the infrared, so if you look at it with a telescope that sees IR like the Spitzer Space Telescope, what is invisible becomes ethereally visible:

This mosaic shows the North America Nebula in different wavelengths of light: in the upper left is visible light; the upper right is visible plus infrared, so you can see the two together; the lower left shows infrared light from 3.6 to 8 microns (roughly 5 – 11 times the longest wavelength the human eye can detect), and the lower right is similar but going out to 24 microns, over 30 times the wavelength we can see. The visible light images show the gas, while the infrared show not only the dust, but the warm spots where stars are being born, their new light penetrating the surrounding cocoons of material, reaching across space, and finally ending its journey here on Earth where we can detect it and learn from it.

I’ve struck upon many ideas for this blog over the past seven years, six months, and one week I’ve been writing it, but one of the most important is this: not everything is as it seems. Whether it’s someone’s opinion, a "fact", a picture, an argument, or even a vast sprawling cloud of gas and baby stars a thousand trillion kilometers across, this much is what astronomy and critical thinking has taught me: What you see depends very much on how you see it. And if you want a more complete picture, something that ever-approaches reality, you must view the Universe with different eyes and with an open, but trained mind. Only then will you not get fooled, and not fool yourself.

Thank you honestly and sincerely to everyone who’s been along with me this far into the ride, here on my 7000th milestone. There’s still a long way to go, of course, but it’s the journey itself that’s so much fun!

Image credits: CĂ©sar CantĂș; NASA/JPL-Caltech/L. Rebull (SSC/Caltech)/D. De Martin


Comments (28)

  1. Bob

    Congratulations Phil! I hope we’re all her for number 70,000! Surely there’s enough material for that many entries…

  2. So … Happy 7000th post! But also happy 7001th, 7002th … as soon as you write them!

  3. Gary

    Even a trained mind can be fooled. So it’s important to periodically reexamine possible sources of prejudice. Maybe the trained mind is even more likely to be fooled since it gets ossified in standard ways of thinking. So it’s extra important to act upon the discovery of something that no longer seems quite right.

  4. We don’t know where North America is. It must be around somewhere. It was pretty bad when we were finding galaxies. How do you misplace a whole galaxy? Is this Bad Astronomy or what?

  5. Shay

    So true Phil, I paraphrase but someone famous said this “We don’t see things as they are, we see things as we are.” Thanks for all the good work you’re doing to move us collectively forward in the many areas of your interest! Keep up the hard and good work!

  6. carbonUnit

    Great work, Phil. I honestly don’t see how you find the time to do all the things you do!

  7. theoncomingstorm

    And you don’t look a day over 2000. Post entries that is.

  8. Daniel J. Andrews

    I saw something new today—the North American nebula, which always looked like North America, looks like a profile of Frankenstein’s creation roaring (profile facing to the right). Even see the teeth. Next time I look through binoculars for it, I’ll see if that illusion still holds.

  9. Chris A.

    For what it’s worth, this image also includes the “Pelican Nebula” (IC 5067/IC 5070, the brightly glowing bit to the right of the North America Nebula–although it doesn’t look very pelican-y in Mr. Cantu’s beautiful image–it’s a bit more obvious in the upper left image of the multi-spectral montage).

  10. Eric

    Happy 7000th! Does anyone know where I can find an archive of all blog posts, if such a page exists? I was looking around links on this page and the old site couldn’t find anything. Google also wasn’t able to find it for me. TIA. I’d like to go read some of BA’s first posts.

  11. Brian


    A blog is really its own archive. There isn’t a nice page just listing titles and links, but a blog’s homepage is just a reverse-ordered list of all posts. If you go to the end of that list, which is currently:


    you can start reading from the beginning, and then proceed to page 999, 998, etc. Note that the blog just happens to show seven entries per page, which is why the first page is a round number. As soon as Phil adds another post the first entry will get pushed to page 1001.

    You can also view a single month at a time as another way to browse around. The first post was in March 2005, so to see the first month of posts, you can use the URL:


    And so on.

  12. thetentman
  13. Pete Jackson

    Thank you, Phil, for the greatest science-astronomy blog out there!

    Beautiful images of the North American nebula. To help interpret what you see, things radiate most strongly at wavelengths in microns that equal 3000 divided by their temperature in degrees Kelvin. This can be reversed as temperature in degrees Kelvin equals 3000 divided by wavelength in microns. Emission-line radiation can mess up this simple relation, however.

  14. Crudely Wrott

    @Daniel, #8

    I, too, saw the N.A. Nebula as a Frankenstein profile and it looks like it’s just about to take a head-butt from a Rockem Sockem Robot!

    Like Phil says, what you see depends very much on how you see it. Just as the appellation of North America was given to the nebula in the first place and my perception of the old game toy. A lot can be gleaned just from the names of things including the nature of the namers.

    Congratulations, Phil. And many thanks for making all of this wonderful stuff available and understandable. You’re gonna get famous if you keep this up.

    Here’s to 14,000. Salute!

  15. Chris

    OK, first blog post was March 13, 2005. It is now Sept. 21, 2012. This is 2749 days. That’s an average of 2.55 blog posts per day. If you continue at the current pace, blog post 10,000 will occur on December 13, 2015!

  16. Messier Tidy Upper

    Congratulations, BA. Well done, very impressive and may there be many more millennia of postings to come! 8)

    Thanks for having us along and sharing your thoughts, discoveries fave images, views and so much more Phil.

    I’ve certainly enjoyed and learnt from reading and arguing here over the years and am not kidding when I tell you yours is my all time favourite blog. :-)

    @14. Crudely Wrott :“You’re gonna get famous if you keep this up.”

    Get famous? You know with his TV show, books and blogs, I’d say he pretty much already was! 😉

  17. Chris

    @14. Crudely Wrott :“You’re gonna get famous if you keep this up.”

    I wonder if he has astronomy groupies 😛

  18. It’s not a galaxy? Well, shoot, there goes the whole plot of one of my favorite 50s issues of “Mystery in Space”!

  19. Zathras

    @14 “You’re gonna get famous if you keep this up”

    Hey, I already refer to the Bad Astronomer as “Dr. Phil” when I talk about the sky and astronomy with my family….What’s worse is that they aren’t confused about who I’m referring to anymore, either 😉

    Just finished watching “Bad Universe” on DVD about a week ago…great show, but I thought Phil was having WAY too much fun trying to blow things up! He made me think of Rico the penguin from the movie Madagascar: “Kaboom boss? Kaboom???”
    Yes, Dr. Phil….KABOOM!

  20. Hah, I’ve got somewhat more views on my blog (including my own)! Thank You and Congratulations, BA & Phil!

  21. Astroblue

    “That’s a lot of words. It’s also a lot of astronomy, geekery, science, antiscience, web comics, puns, embiggenates, and “Holy Haleakala!”s”

    And a lot of love, too. :)

    I learned a lot from your blog and love it.

    Thank you, Dr. Bad Astronomer!

  22. PhilippeC

    Oh my! I think I read most of these 7000 posts….
    This means I’ve spent a lot of time absorbing your knowledge of the universe…

    But didn’t you start debunking bad science in movies even before that, on your own blog (before discover magazine) ?

  23. Jess Tauber

    62 is not arbitrary. Nickel-62 (with 28 protons and 34 neutrons) is the most densely packed nucleus in the entire periodic system. It is also related as the closest whole number 100x the lower value of the Golden Mean. All sorts of things like this show up in the periodic system, and they don’t seem to be arbitrarily or randomly sorted or mapped either. The highest naturally occurring element, plutonium, is atomic number 94, which is twice 47, a Lucas number (just as 34 above is Fibonacci). Now one COULD argue that 47, as in Romney’s 47 percent bums and moochers, is arbitrary, but coming from someone who flips on every issue except salivating over the presidency, would that really be fair? For HIM, this might constitute the closest the quantum-indeterminacy candidate comes to dropping out of state superposition.

  24. Scottynuke

    Keep it up, Phil, and we’ll soon need the Webb to see all the way back to the beginning of the blog! Well done, and my sincere thanks for all you do!

  25. Diederick

    Thank you, and congratulations.

  26. colin

    Without doubt my favourite bit is the cows head

  27. Todd

    Hey Phil, Congrats on the 7k!

    I’ve loved the blog for ages and my wife loves the pics and time-lapseseseseses!

    Cheers friend.

  28. Jon Hanford

    I see where Phil mentions that Deneb may be the illuminating star for the North American Nebula. However, other stars have been proposed to illuminate this nebula. In 2005, a pair of astronomers proposed that a heavily obscured O5V star, 2MASS J205551.25+435224.6, was responsible for illuminating both the North American and Pelican nebulae:



    I haven’t seen any followup to this paper, but they make a reasonable argument for their candidate star.


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