Lying roughly 50 million light years from Earth is the magnificent spiral galaxy NGC 5033. Although that distance is a soul-crushing 500 quintillion kilometers, it’s actually relatively close by on the cosmic scale. Close enough that a lot of detail can be seen in the galaxy… and it also makes for a stunner of a picture:

[Click to darmokenate.]

This shot was taken by friend-of-the-BA-blog Adam Block using the 0.8 meter Schulman Telescope on Mount Lemmon in Arizona. It’s a whopping 13 hour exposure taken in near-true color.

It’s amazing what you can see in just this picture if you know what to look for. The spiral arms of the galaxy are fairly open, which is common enough, but the outer ones stick out a bit more than you might expect. The nucleus is very small and bright, more so than I’d expect for a typical spiral as well. Both of those things led me to expect this is an active galaxy, and that turns out to be the case.

Every big galaxy – ours included – has a supermassive black hole in the center. The Milky Way’s is 4 million ...

Alan Friedman’s photos are no stranger to this blog; I’ve posted a lot of his amazing pictures of the Sun (See Related Posts, below). So many, in fact, that one needs to be surpassingly cool to add to the lineup.

So, yeah:

[Click to ensolarnate.]

Yegads. He took this on July 29, 2012. Because the image is inverted – dark things appear bright, and vice-versa – sunspots are intense white patches, bright plages appear dark, and towering filaments are whitish-gray.

Note how the Sun’s face gets darker toward the center and brighter toward the edge – meaning in reality the center is bright and the edge dimmer. This is called limb-darkening (the opposite of limb-brightening seen in some gas clouds), and occurs because gas around the Sun absorbs its light. We look through more of it near the edge than toward the center, so there’s less light coming from the limb of the Sun.

I’ll note that only the face of the Sun is inverted, though. Everything outside that is normal, so the leaping prominences of gas on the edge are ...

My Italian is a little rusty, so I hope I got the title right. Either way, here’s what I was referring to:

Isn’t that gorgeous? It’s Italy, of course, seen on August 18, 2012, at night by astronauts aboard the International Space Station. The ISS was well to the southeast, probably over Libya or Egypt in Africa, when the astronaut took this shot facing northwest. I poked around a bit, and the ISS was in this position twice on that date. Once was during the day, and the other around local midnight, so that fits.

It’s pretty neat to see Italy from space; I’ve posted an image like this before (though the ISS was much more overhead for that one). In this one you can see the arc of green airglow caused by oxygen atoms about 100 kilometers up giving up energy after getting whacked by ultraviolet light from the Sun. To the left and along the top you can see some of the ISS structures, too.

I’ll note that on Thursday, August 23, NASA announced that the private company SpaceX had ...

On the morning of August 13 – 14 (depending on where you were in the world) the Moon slipped directly in front of Venus in the sky, an event called an occultation. It was cloudy here in Boulder so I missed it, but halfway across the world in Korea, astrophotographer Kwon O Chul had a magnificent view, and made this lovely time lapse video of the event.

Occultations like this are relatively rare. If all the planets and moons orbited the Sun in exactly the same plane – that is, if you looked at the solar system from the side and all the orbits aligned perfectly, like looking at a DVD from the side – we’d see occultations all the time.

But in reality all the orbits are tilted a little bit. Venus circles the Sun in an orbit canted by about 3° compared to Earth’s. The Moon’s orbit is tilted by 5 °. The Moon orbits the Earth once per month or so, but it usually passes by Venus, missing it by a bit because the orbits aren’t aligned. But sometimes, every few years, the dance comes together, and the Moon wil slip directly ...

I am very excited to invite everyone to a fantastic event: RocketFest, a field day at Space Camp in Huntsville, Alabama!

Rocketfest is a celebration of Space Camp and what it does to inspire kids to explore space. It’s open to families and kids of all ages, and it’ll be on Monday, September 3rd, 2012 from 10:00 a.m. to 4:00 p.m. at Space Camp itself. All proceeds raised go to the U.S. Space & Rocket Center Foundation.

I’ll be giving a short talk there about space exploration, and a few geeky friends will be there too: George Hrab, Molly Lewis, Ken Plume, Joseph Scrimshaw, and Marian Call! Marian organized this whole thing because she is constructed of awesome. Also, ThinkGeek is donating prizes for it, too.

Marian has details on her blog, and you can read more about it on the Space Camp page, or the Facebook events page Marian set up.

The event will be streamed live on the web from the Space Camp page. I’ll try to tweet ...

Bill Nye speaks the truth.

[Video credit: Big Think]

In science, it’s rare that you can actually state with certainty that something is wrong. Young-Earth creationism is wrong. The Universe is old.

However, I’ll disagree with Bill over one thing, and I’ll throw Neil Tyson into the mix too. First, here’s something Neil said about adults, children, and nonsense (from an image that’s gone around the web a few times):

Funny, Neil and Bill are saying the same thing, essentially, but Neil is saying he doesn’t worry about the kids, while Bill is saying he doesn’t worry about the adults.

I worry about both, for, oddly enough, the reasons Bill and Neil both give. We have entrenched adults teaching things to their kids that are clearly wrong, and will be damaging to them and others. Creationism, global warming denial, antivaccination, ridiculous ideas about women and their bodies… it’s a cycle from adults to kids who then grow up to teach more kids.

We need to break this cycle. Make sure the education kids get in school is reality-based. Keep religion (or the lack thereof) out of ...

Hurricane Isaac is hitting the Gulf coast of the US right now, battering the area with 120 kph winds. Just after local midnight on August 28, the Suomi NPP Earth-observing satellite took this eerie and beautiful picture of Isaac when it was still a growing tropical storm:

[Click to encoriolisenate; bigger versions are available on Flickr.]

This picture is a combination of several images taken in different filters, including is in the visible light and infrared, and uses light intensifiers to make faint things viewable [Note: this is actually one image, not a composition of several filtered images. Thanks to Robert Simmon for the correction!]. The waxing gibbous (just past half-full) Moon didn’t set until after 2:00 a.m. local time, so it’s possible the cloud illumination here was coming from that. And of course you can see the city lights, including New Orleans already under the outer bands of the storm.

NASA’s Earth Observatory just posted another, more recent picture in visible light from the Terra satellite, too.

Pictures of hurricanes from space are amazing. As always, there’s a fascinating dichotomy to pictures like this, a ...

Oh, this is too cool: scientists have found a planet orbiting a binary star (a pair of stars in tight orbit around each other) that is at the right distance to have liquid water! Let me be clear: this planet is much bigger than Earth, and is likely to be a gas giant. So it’s not Earth-like, and probably not itself habitable.

But it might have moons…

[Note: this image is artwork based on the science. Click to tatooineneate.]

OK, first: Kepler is an orbiting telescope that has been staring at one spot in the sky for about three years now. It’s looking at about 100,000 stars. If these stars have planets, and the orbits of these planets are seen edge-on, then they will occasionally pass directly between us and their parent star blocking a little bit of the light. This is called a transit, and if the planet is big enough it can block enough light from the star to be detected by Kepler. So far, 77 planets have been confirmed using Kepler, and over 2000 more have been detected and are awaiting confirmation. ...

[BAFacts are short, tweetable astronomy/space facts that I post every day. On some occasions, they wind up needing a bit of a mathematical explanation. The math is pretty easy, and it adds a lot of coolness, which I'm passing on to you! You're welcome.]

Today’s BAFact: How much brighter is the Sun than the faintest object ever seen? About Avogadro’s number times brighter.

Yesterday and the day before I wrote about how much brighter the Sun is than the Moon, and how much brighter the Sun is than the faintest star you can see (note that here I mean apparent brightness, that is, how bright it is in the sky, not how luminous it actually is). I have one more thing to add here.

Years ago, I worked on a Hubble Space Telescope camera called STIS – the Space Telescope Imaging Spectrograph. At the time, it was the most sensitive camera ever flown in space, and I was constantly amazed at what we saw using it.

Hubble did a series of observations called the ...

There is a whole lot of awesome in a picture of Saturn and its rings just released from the Cassini spacecraft. Check this out:

Mmmmm, ringalicious.

Cassini was about 2 million kilometers (1.2 million miles) from Saturn when it took this picture, so we’re seeing a decently wide-angle view. At the time, the spacecraft was below the plane of the rings, looking north (up, if you like). The Sun is off mostly to the left and up a bit.

The first cool thing is obviously the shadow of the planet itself cast on the rings. It cuts across like a black scythe! As I looked at the picture my eyes and brain kept trying to fill in the missing arc of rings, which was amplified by a slight afterimage as my eyes moved around. It’s a difficult illusion to ignore.

Second, I love how you can see all the different rings in the picture, including the thin, lumpy F-ring outside the main band. The big gap is called the Cassini Division; it’s not really an empty space since there are many faint thin rings inside it. They’re just hard ...

Now that I’ve properly recovered from Comic Con in July, it’s time for Dragon*Con! Woohoo!

D*C is another huge fan convention, held in Atlanta, and this year it’s Friday August 31 to Monday, September 3. As usual, I’ll be running around doing a million things and wondering if a human can survive on Tootsie Rolls and 4 hours of sleep every night (answer: yes). If you’re attending, here’s my official schedule for this year:

Title: Quiz-o-Tron 2000
Time: Fri 10:00 pm Location: International South – Hyatt
Description: Rebecca Watson’s science-themed quiz show!

Title: Gonzoroo II
Time: Sat 08:30 pm Location: Atrium Ballroom – Marriott (Length: 2.5)
Description: An evening of music, comedic delights, and surprises galore!

Title: The Kevin & Phil Show
Time: Sat 10:00 pm Location: Crystal Ballroom – Hilton (Length: 1)
Description: Space Track’s comedy duo! Topical, engaging, informative & always funny! Whatever the subject, you don’t want to miss it!

Title: 2012 – Don’t Panic!
Time: Sun 10:00 am Location: Crystal Ballroom – Hilton (Length: 1)
Description: Panicking about 2012? Nope, not panicking until Phil Plait gets a role on the next Twilight film or Scott Sigler ...

I know, I’ve posted a few of these, but a new video came out showing the descent of Curiosity to the surface of Mars that’s worth a look.

YouTube user "hahahaspam" did a clever thing. The Mars Descent Imager (MARDI) is a camera that points straight down, past the rover, so engineers on Earth could later see the exact path Curiosity took on its way down to the Martian surface and also get an overview of the area. It took a series of images that were later put together to make various animations (see Related Posts below). The motion appears jerky because the camera only took about four pictures per second.

What hahahaspam did was interpolate between the frames, making the motion appear much more smooth. The animation he made is really quite wonderful:

Nice, huh? Interpolation is a math term that involves estimating the value of something between two measurements. A simple example involves someone running. You measure their progress: after one second they’ve traveled 2 meters, and after two seconds they’ve run 4 meters. How far did they get in 1.5 seconds?

Obviously, the answer is 3 meters. It may not be exact – a person’s running ...

[BAFacts are short, tweetable astronomy/space facts that I post every day. On some occasions, they wind up needing a bit of a mathematical explanation. The math is pretty easy, and it adds a lot of coolness, which I'm passing on to you! You're welcome.]

Today’s BAFact: The Sun is 12 trillion times brighter than the faintest star you can see with your naked eye.

In yesterday’s BAFact, I showed how the Sun is about 400,000 times brighter than the full Moon – and I showed my math. That’s an amazing brightness difference, but while I was writing it I had to wonder: how much brighter is the Sun than the faintest star you can see?

The faintest stars visible to the naked eye have a magnitude of about 6. This depends on lots of stuff, like how dark the sky is, how good your eyesight is, and so on. Some people with excellent vision can see stars down to magnitude 7, and there are reports of a few extraordinary people who can see even fainter. But on a dark night, the average person can just ...

The Curiosity rover is still going through its shake down phase, using new equipment and making sure all is well. A few days ago, engineers fired up its 100 mm camera – a telephoto that has a bit more zoom to it than the cameras from which we’ve been seeing pictures. They pointed it to the base of Mount Sharp, the big mountain in the center of its new home of Gale Crater. And what it saw is, simply, breath-taking:

Holy moley. That’s fantastic! [Click to barsoomenate.]

It looks a lot like rock formations I’ve seen in Arizona and Utah… but then, the geologic processes that formed this region are similar. At some point in the past it was flooded with water, and looking at the layering this happened many, many times. The sediments built up and then were worn away over the eons, forming this gorgeous striped sedimentary rock.

Inset here is part of the same scene with distances to various landmarks labeled [click to embiggen]. It looks like there’s the edge of a hill 230 meters ...

Earlier, I wrote that arctic sea ice had yesterday reached record low levels, blowing through the previous lowest-seen minimum in 2007, even though there’s still a lot of melting left to go.

NASA just released this visualization of the arctic region showing just how bad it is:

The white area is the extent of sea ice as of August 26, 2012. The orange line is the average minimum extent from 1979 – 2010, the time covered by satellite observations. In other words, every year they measure the outline of the ice when it reaches its minimum, usually in September, and then averaged those positions for that timespan.

As you can see, we’ve been well below the usual minimum ice extent for some time – not just where we usually are this time of year, but the actual minimum amount… and we still have weeks of melting yet to go.

I want to note that this does not necessarily mean we’ll see sea level rising from this. That ice is floating on the water, and in general when ice melts the water level stays the same. You ...

[BAFacts are short, tweetable astronomy/space facts that I post every day. On some occasions, they wind up needing a bit of a mathematical explanation. The math is pretty easy, and it adds a lot of coolness, which I'm passing on to you! You're welcome.]

Today’s BAFact: The Sun is 400,000 times brighter than the full Moon in the sky.

If you’ve ever looked at the full Moon through a telescope you know how painfully bright it can be. But you can do it if you squint, or use a mild filter to block some of the light.

On the other hand, if you try the same thing with the Sun (hint: don’t) you’ll end up with a fried retina and an eyeball filled with boiling vitreous humor.

So duh, the Sun is much brighter than the Moon. But how much brighter?

Astronomers use a brightness system called magnitudes. It’s actually been around for thousands of years, first contrived by the Greek astronomer Hipparchus. It’s a little weird: first, it’s not linear. That is, an object ...

I’ve been holding off writing about this until it was official, and now it is: the area of the arctic covered by sea ice has reached a record low.

[Click to embiggen.]

"Sea ice extent" is (more or less) a measure of the amount of ice covering the sea surface. It’s measured using satellite data; the area is divided into many bins, and sea ice extent is calculated by adding up all the bins with more than 15% ice in them. Every year the ice starts to grow in the autumn and melts in the summer, so you get a sine-wave curve of extent every year.

Satellite observations began in 1979. In the graph above, the dark line is the average summer extent for the period 1979 – 2000. The gray area around it is the measurement uncertainty (2σ if you want to be exact). The dashed green line is the extent for 2007 – the previous record low year – and the blue line is 2012. I added the red line so you can compare 2007 to now. The data numbers show the record is ...

[I was going to wait to post this until next week, but with Neil Armstrong's death I've decided to put it up now. If he could risk his life open up the Moon as a world for all mankind, the least I can do is share it as much as I can.]

If you need a little extra dollop of awesome in your day, then try zooming in and flying over the surface of the Moon, care of astronomer Pete Lawrence’s incredible mosaic of our nearest cosmic neighbor:

[You may need to refresh this page if you don't see the Moon picture directly above this sentence.]

Click the button on the lower right that makes the picture expand to fit the browser, then zoom in and out using the + and - buttons. Click and drag to fly around. Make vrooom vroom noises.

Make sure you zoom in all the way and then cruise over the terminator, the day/night line. Trust me.

This ridiculously cool image is composed of 166 separate sub-images taken over the course of just 45 minutes on August 10, 2012. He used a Celestron 14" with a video camera. Get this: each of the 166 sub-images is ...

The first human to set foot on another world has died. Apollo 11 astronaut Neil Armstrong was 82.

There is so much that can be said about this man, from his incredible career to his notorious shying away from the spotlight. He had history thrust upon him, and performed in a way that will be an inspiration to generations of explorers.

I’ve said many times that we can divide all of history into two parts: before humans landed on the Moon, and after. It was not just an important moment, it was the moment, a defining, crystallizing slice of time that confirmed that we humans had become a space faring race. One world could not and would not contain us, and the sky itself was no longer the limit.

We have had our missteps since that one small step, and we can argue about the directions we are or should be taking. But given what we’ve done, and what we are capable of, I have the spark of hope that the future will look back at July 1969 and recognize it for what it was: the dawn of a new ...

I have a very odd coincidence to report.

I like getting fun questions from folks, the kind that take a little bit of math and physics to explain, but wind up taking you to fun places. A common question like that is, "What would happen if everyone in China jumped all at once?" Would it throw the Earth out of orbit? Would it cause an earthquake? Would it do anything?

The answer is, essentially, no. I tackled this a few years back; there was this announcement by a group that wanted to get 600 million people to all jump at once so that the Earth would be pushed farther from the Sun and global warming would be solved.

Um, yeah. They called it World Jump Day, and I made quick work of it. Nothing at all would happen, for lots of reasons. Still, it’s fun to think about, right? And it turns out World Jump Day was something of a prank anyway.

And that’s where the coincidence I mentioned comes in. I recently happened to see a video done by vsauce asking this very question. He handles it really well in an entertaining video: