So Curiosity’s been on the Martian surface for a week, and we’re already seeing faked images touted as being real. The other day it was a more-or-less honest mistake of people spreading around a computer-generated view from Mars – originally meant just to show what the skyline looked like from there – thinking it was real.
Now though, we have what’s clearly an actual fake. Here’s the shot, getting passed around on various Tumblrs:
Now, I’ll note it’s not crazy to think this shot might be real; the Sun is very bright and in many cameras you can get reflections inside the optics, causing this double-Sun effect. It happens all the time. So you wouldn’t really be seeing two suns setting – just one real one and one that’s an internal reflection.
But that’s not what’s going on here, as I knew right away. That’s because I’m familiar with this picture:
That shot is also of the sunset, but it really is from Mars! It was taken by the Spirit rover in May 2005, a spectacular shot of the Sun setting over the Martian landscape.
And that’s where you’ll find the proof of double-sunset-fakery. Compare the double-sunset picture with the real one from Spirit, and you’ll see the profile of the landscape on the horizon is exactly the same. Clearly, the double-sunset pic was faked, adding in the second Sun. In fact, you can see that both images of the "Sun" in the double sunset picture don’t match the real one. In other words, both images of the Sun were faked.
Also, I couldn’t help but think the faked Sun images looked kinda familiar to me as well. Recognize them? Perhaps the picture here will help place them. Clearly, the faker must have come from some wretched hive of scum and villainy.
It may be this picture was created as a joke and got out into the wild, or maybe it was done on purpose to fool people. As usual with things like this, tracing it back to the original is a bit tough (though the Martian skyline picture from earlier was able to be pedigreed). I’ve seen it on several sites now, and I’ve gotten email and tweets about it. It was easy to debunk, so why not?
I don’t know if this image will go viral like the previous unreal one did; this is so obviously hoaxed that it may not have the same sort of traction. Still, it sometimes helps to get ahead of the curve here, and dowse these things with reality before they spread out of hand.
So if you see someone posting that image, send ‘em here. That way, we will crush the hoaxers with one swift stroke.
Image Credits: Mars sunset: NASA/JPL/Texas A&M/Cornell; Tatooine: Uncle Owen’s Wedding Photography Service (now defunct).
What would sunset look like if you were on the planet HD209458b, a gas giant orbiting a star 150 light years away? According to exoplanetary scientist Frédéric Pont, it looks like this:
Isn’t that pretty? And there’s quite a bit of science in that, too.
First things first: HD209458 is a star pretty similar to our Sun. It was one of the first stars determined to have a planet orbiting it (way back in 1999) — the aforementioned HD209458b, nicknamed Osiris — and it turns out the planet’s orbit is so close to edge-on as seen from Earth that we see that planet passing directly in between us and that star once per orbit. When the planet transits that star the amount of light we see dips a little bit. From that we can get the period of the orbit and the size of the planet (a bigger planet blocks more light).
But we can get more, too. There’s a camera on board Hubble called the Space Telescope Imaging Spectrograph, or STIS. It can take the light from an object and break it up into thousands of separate narrowly sliced colors, called a spectrum. By analyzing that spectrum we can find out an astonishing amount of things about astronomical objects: their temperature, rotation, even their composition!
Shortly after HD209458b was discovered to be a transiting exoplanet, STIS was pointed at the star. The camera took hundreds of very short exposures during a transit in the hope of being able to detect the atmosphere of the planet. Osiris was known to be massive, about 70% as massive as Jupiter, so it most likely has a thick atmosphere. It also orbits so close to its parent star — 6.7 million km (4 million miles), much closer than Mercury orbits the Sun — that the heat from the star puffs the atmosphere up, making it easier to see.
In fact, the spectra did reveal the presence of an atmosphere; the first time the atmosphere of an alien planet was ever observed. Different elements and molecules absorb light at different colors, so in the spectrum there are dark spots where the planet’s air absorbs the light from the star behind it during a transit, and how dark that spot gets tells you how much light is absorbed.
It’s this information Prof. Pont used to create the image above (inspired by investigation and an animation done by Alain Lecavelier des Etangs). By knowing the color of the star itself, and using the way the planet’s atmosphere absorbs light, he created this image of the star using sophisticated computer modeling. Read More
There’s a wonderful comedic quiz show in the UK called "QI" — for "Quite Interesting" — which is hosted by none other than Stephen Fry. The participants are comedians, and they’re asked questions ranging over just about every topic you can imagine. The BBC recently uploaded a clip about which alert BA Bloggee Brett Warburton informed me. In it, Fry shows the contestants a video of the Sun setting, and asks them to ring in when they think the Sun has completely set. Here’s the clip:
This is, in fact, correct! The Earth’s air bends the image of the Sun upward, so we can still see the Sun even though it is physically below the horizon. If we didn’t have air, daytime would be shorter. In fact, this effect works for sunrise as well, so we see the Sun rise before it’s physically cleared the horizon.
And Stephen was correct in the amount too; the light is bent upward by just about the same size as the Sun, so when the lower limb of the Sun just kisses the horizon it’s actually already set.
But it’s a bit more complicated, of course. Read More
Every few months, like clockwork, someone sends me an email telling me about a lovely picture they’ve seen. This photo, it’s claimed, shows a sunset at the north pole with the crescent Moon looming hugely over the horizon. Perhaps you’ve seen it via email or a social network; the picture really is stunning, as you can see for yourself:
It is pretty, isn’t it? But it has one teeny tiny problem: It’s not a photograph! It’s a drawing, called “Hideaway”, created by Inga Nielsen. It’s a really, really good drawing, beautifully done, so realistic it can fool people into thinking it’s a photo. I’ve seen people thinking so on bulletin boards for years, and in fact it just popped up again, this time on Google+. And, as usual, a lot of folks thought it was real.
I can’t blame them, since it’s photo-realistic, as many digital drawings are these days. And if you see this without attribution to the artist, and don’t know the astronomy behind the scene, it’s hard to say whether it’s real or not.
So how can I tell it’s a drawing? Ah. Glad you asked.
Size does matter
Right away, the size of the Moon in the picture compared to the size of the Sun is a dead giveaway this isn’t a real photograph. In the real sky, the Moon and Sun appear to be the same size.
[Note: ROSAT fell to Earth last night; see this post for details and links to more info.]
Time lapse videos can be breathtaking, lovely, and a joy to watch… but they can also show you something you may not have thought about before. Before I even read the caption for Murray Fredericks’ video called "IRIDIUM", I knew it was filmed in the southern hemisphere. Can you guess how?
[Make sure to watch it in HD, and make it full screen.]
If you live in the northern hemisphere — and odds are very good that you do — then you may have noticed the motion of the Sun and stars looked a bit odd. For example, as you watch the Sun set at the beginning of the video, it does so at an angle moving from the upper right to the lower left. The stars do too. When they rise, they move from the lower right to the upper left.
To me that’s backwards!
I know this isn’t strictly astronomy, but it’s a lovely time lapse video of sunrises and sunsets in the arctic… and since the Earth is tilted, in the summer the Sun skims just below the horizon as it circles the sky. So hey, I guess it is astronomy related!
You can really see this effect well starting at 1:06 into the video; the Sun sets at a very low angle to the ground, and comes right back up. The sky never gets completely dark.
The video was shot by a man who calls himself Mr. TSO, and he has many other lovely videos on Vimeo. It’s Friday, so take some time and look. You’ll breathe just a little bit easier if you do.
– Gorgeous Milky Way Time Lapse
– Very Large Telescope, Very Stunning Time Lapse Video
– Incredibly, impossibly beautiful time lapse video
– Dust, from the desert below to the galaxy above
– Stunning winter sky timelapse video: Sub Zero
– OK, because I like y’all: bonus aurora timelapse video
– AWESOME timelapse video: Rapture
If we didn’t go into space, we’d never see such beauty as this:
Sunset over Bolivia, as seen by astronauts aboard the International Space Station. Click it to get the glorious full size version.
And you know, this isn’t the reason to go into space, but it’s not a bad one. Not a bad one at all.
I know, it may not look like much, but think about what you’re seeing: a sunset on another world. And those images were taken by a robotic probe that took years to design and build, months to travel the hundreds of millions of kilometers to get to Mars, a harrowing few minutes to descend on a breath of fire through the thin air to land on the surface, and then nearly seven years to travel the landscape long, long past its design specifications.
All that, plus all the amazing science, exploration, and discovery done by Opportunity and its sister rover Spirit… and yet, it’s sometimes the stark beauty of simple things like this that remind us that we have, at least by proxy, placed our feet on other worlds.
I know there are worries here on Earth. But when I see something like this, I remember that the good we do, the awe we feel, and the inspiration we can generate are mighty.
Tip of the pancam to Emily Lakdawalla on Twitter.
What does a sunset look like when you’re racing through space at 8000 meters per second?
Oh, I could go on and on about the curvature of the Earth, the layers of the atmosphere, the distribution of colors, how the aerosol layer is thin and glows after sunset, and what it must be like to go through 16 sunrises and sunsets every day. But you can get all that information from the NASA website. And really, the enduring nature of this picture is not what it shows, but that it was taken by a human being in space.
This is without doubt the single greatest thing on Earth, and the very reason the Internet was invented.
Sure, I came for the one about Doctor Who, but stayed for the rest of the magnificence that unfolded before me.
My hat is off to you, sir. Kudos. Kudos, indeed.
Tip o’ the brain and brain, what is brain? to BABloggee Oliver X for making my life so wonderfully better with this.