And the cover art was designed by Space Tweep Society founder, Jen Scheer!

Other space news… Carnival of Space #148 is up at Celestial Spider!

Click a twitpic!

Don’t yet know your radio astronomy alphabet soup? ALMA is the Atacama Large Millimeter/Submillimeter Array, a really powerful radio interferometer that will probe the sky with much higher sensitivity in the millimeter and submillimeter wavelengths than ever before. Astronomers will be able to do groundbreaking research in star formation, planet formation, galaxy evolution, and more. Yeah, it’s a big deal. The telescope itself is being constructed at the “high site” of 16,000 ft (5000 m) called the AOS, or Array Operations Site. That’s a wee bit high for we oxygen breathing humans to work comfortably every day, so the base of operations is the OSF, or Operations Support Facility, at an altitude of “just” 9,500 ft (2900 m). The OSF is what was captured by the orbiting astronaut. Cool.

Get more of your weekly space fix at the Carnival of Space #147 at WeirdSciences!

Tomorrow is a special blogging event… Ada Lovelace Day! I’m looking forward to reading all kinds of stories of trailblazing ladies in science and technology. My own post will go up tonight! It’s not too late to pledge if you want to write about a woman that has inspired you.

Also debuting tomorrow is a project by the lovely Heidi Anderson, SheThought.com. This is going to be a great place to discuss women, skepticism, and science. See you there!

A parsec is a measure of distance. But, you are thinking, Nicole, don’t you astronomers already use the light year as a measure of distance? A light year is the distance that light travels in one year, so it is a convenient measure of distance to explain. (It’s about 5,878,630,000,000 miles, if you are curious.) However, astronomers actually use a unit of distance that makes more physical sense with respect to how we measure distances.

The name “parsec” is pretty self-explanatory once you know what two jargon-y words it’s made of. It is defined as the distance that an object is from Earth to create a parallax of one arcsecond.

Hold out your finger at arms length. No, really, do it. I’ll wait. I won’t laugh! Promise. Okay, now close one eye and note what your finger is in front of. Now, open that and close the other. Notice a difference? Compared to some background object, your finger has appeared to move, no matter how still you keep it. That is essentially parallax.

Now, take this system on a grander scale. Each one of your eyes was a point of view. Replace that with the orbit of the Earth, with one point of view 180 degrees around the orbit from the other. Your finger is now some star to which you would like to know the distance. The background of your room is the background of more distant stars and galaxies. A parallax observer takes pictures of their target star six months apart and measures the change in position against the background of stars that are too distant to show this effect. From that measurement, they can tell the distance thanks to a little geometry.

This picture is very much NOT to scale since the distance to any star is much, much greater than the size of the Earth’s orbit. So, we can use some handy approximations to calculate the distance. See that right triangle? We can pull out from our trigonometry background that

tan(p) = (distance from Earth to Sun) / (distance from Sun to star).

But with the “small angle approximation” and using the definition of the distance from the Earth to the Sun (Astronomical Unit, AU, approximately 93 million miles), we get

p = 1 AU / d

Using just the right units, and doing a little switching around, we get just

d = 1 / p

The unit of measure for p is arcseconds, which is a tiny, tiny angle. If you break a circle into 360 wedges, each one is one degree. If you break that wedge into 60 wedges, each is an arcminute. Split up one of those 60 ways, and you get an arcsecond. Another way to see how tiny that is…. hold up your index finger at arms length again. The width of your finger is about 1 degree. So an arcsecond is 1/3600 the width of your finger. Need I say… TINY! A star that measures a parallax of one arcsecond is now one parsec away.

So how far is a parsec really? If a one-arcsecond measurement is so tiny, then a distance of one parsec must be really far away. And it is, on human scales, but the nearest star is 1.3 parsecs away. The center of our Milky Way galaxy is almost 8000 parsecs away, or 8 kiloparsecs*. Cygnus A, one of my favorite radio galaxies, is 230 million parsecs (or 230 megaparsecs) away. Yeah, this stuff is FAR!

How do parsecs compare to the more-easily-explained light year? Well, one parsec is approximately 3.26 light years. If you ask me the distance to some celestial object, if I know it at all, I probably know it in parsecs, and will make a quick and dirty calculation in my head to light years before answering. And like its cousin the light year, the parsec has been mistaken for a measure of time.

Now, before you go off on your own parsec-scale adventure, check out the newest Carnival of Space #145 at Crowlspace.

*Edit: I should be a little more careful with my significant figures. We don’t know the distance all that accurately! Thanks @leifb

via Chandra, Hubble, and the Very Large Array

Check it all out at Discovery News this week!

Get it? I love… 143? When I was in high school, before cell phones were popular, everyone (but me) had a beeper. We used silly little codes to each other… and 143 meant “I love you.” And my boyfriend’s name at the time was Eddie, which could be spelled out upside down, so I would send him “143 31003″ from our school’s payphone… yeah I’m a dork.

Anyway, that’s far less interesting than the cool stories about Mars avalanches, bad science movies, the sun, and more over at this week’s carnival!

Also, while you are browsing, check out this cool chart of the planets and moons of our solar system and the molecules that have been discovered in their atmospheres! This came up in our seminar on the Atacama Large Millimeter Array which is going to be a boon to astrochemistry.

So, were any of you on Twitter when I was asking specifics about goat noises? Why was I asking that? Well, find out at this week’s Amateur Scientist Podcast, where Brian brings the awesome, Christian brings the funny, and I just try and hang along for the ride. (If you didn’t already know, language NSFW, and sarcasm not safe for Sheldon Cooper.)

That’s all for now… I feel like there was something else, but I can’t remember now. But I also post random, fun, and cool things on Tumblr as well!

SDO stands for Solar Dynamics Observatory. This is the first mission of NASA’s Living With a Star program. We may think that Earth is the most important place in the solar system, but the Sun is the real powerhouse. We who live on this tiny rock in orbit about its fiery bulk must learn to live with what is, in its own way, a variable star.

The sun in extreme UV, as captured throughout one cycle by SOHO

The sun goes through a cycle of high and low activity. This manifests itself in a greater number of sunspots, solar flares, and coronal mass ejections about every eleven years. Sunspots are darkened, cooler areas of the sun, but they tell a tale of force and violence underneath. They are often linked with solar flares, which are explosions in the atmosphere of the sun that occur when magnetic energy is released. In an extremely energetic event, a coronal mass ejection can hurl electrons and protons away from the sun at incredible speeds, averaging 500 miles per hour kilometers per second! If a CME or flare is directed at Earth, these can cause power failures and disrupt satellites. As we become increasingly dependent on our power grids, cell phones, GPS, and yes, even your satellite radio, better forecasting is needed to predict such events. Enter SDO.

SDO has three instruments that will send back data on the Sun simultaneously and 24 hours a day. The Atmospheric Imaging Assembly (AIA) has four telescopes, looking at a total of ten bands, or colors, with super-high definition quality. Continually imaging the Sun’s surface and atmosphere, it will allow scientists to track the evolution of surface features and flares with a time resolution as small as 0.75 seconds. The Helioseismic and Magnetic Imager (HMI) will probe deeply into the sun and map the magnetic field structure. (How? Well, that’s so cool, I’ll devote a whole post to it later this week.) My favorite instrument of the bunch is the Extreme Ultraviolet Variability Experiment (EVE). This does just what the name says, measure the variability of the output of the sun at far-UV wavelengths. Why is that so important? UV light from the sun creates and shapes the ionosphere of the Earth. The ionosphere is the outermost layer of the Earth’s atmosphere, and although it has many beneficial effects on life, it’s a pain for low frequency radio astronomers such as myself. (So, let’s just say this will get a devoted post as well.)

SDO will sit in a geosynchronous orbit above Las Cruces, New Mexico, where a dedicated radio station will be ready to gobble up the 130 Mbps of data that this mission will send back. Project scientists are calling this an “avalanche of data.” This fits in with the trend of many modern telescopes, such as the EVLA and ALMA, producing much more data than astronomers have ever dealt with before. New techniques for handling and distributing these data are always needed.

But, don’t just take it from me. Here’s an official SDO video!

Want to get involved in solar research right now? The premier site for citizen science in astronomy, Zooniverse, has a project called Solar Stormwatch. You learn how to look for and identify solar flares, and then look at some real data from previous missions and discover solar flares better than any automated image recognition software can.

Stay tuned for more updates from KSC as we begin our adventure, and join in at a local or virtual TweetUp for the launch! I’ll be blogging here and posting pictures on Flickr. George is posting his gorgeous (and silly) photos as well!

And while we’re wrapped up in all this spacey goodness, won’t you also check out the most recent Carnival of Space at Mama Joules!

SDO Spacecraft Image

Last week, the very awesome Nancy Atkinson wrote up the Carnival of Space #138 over on her new blog. Check out news about Mars, Kepler’s findings, and more!

I’ve posted a draft of the Twitter poster I had at the AAS Meeting at the beginning of January. It includes some quotes from the survey I put out the week before, though I haven’t compiled all the numbers yet!

For some crazy reason that I’m not even fully aware of, I’ve started a Tumblr. It’ll probably be a dropping off place for random links and photos and things, whereas any actual writing I manage will stay here. Oh, it’ll probably feature some of my real-life potty mouth, which I keep tame here.

And finally, I’m going to Florida! George, Aleya, Aleya’s bro, and I are road-tripping down to Kennedy Space Center for the launch of the Solar Dynamics Observatory! We’ll be tweeting and blogging and posting pictures the whole way. Oh, and we’re also going to get to see the launch of STS-130… my first ever launch, and possibly the last shuttle night launch! Follow the SDO tweetup events with the #SDOisGO hashtag, and I’ll be posting here as well. UPDATED AGAIN: My photos will be uploaded to my new Flickr set.

Boom, baby. STS-128 by cma3.

*NERDSQUEE!!*