We had a great response to historical photos segment. After finishing 20-parts of that segment, we have decided to halt it for a while, and start some other new segment. One such one is Space Images segment. So here is part 1 and stay tuned for more.
Clearest picture of Mercury. In real life, mercury isn’t this blue. Filter was added to the original picture to show rock and mineral make-up. On that note, here is a picture of what Mercury looks like in its real color. On a space craft you can get the most resolution per weight of your camera from a black and white image. True color imagery is pretty, but not terribly useful scientifically, which is why you see so many false color space images. They are using different wave lengths of light to observe different things.
02. Pillars of Creation
Hubble Revisits the Famous “Pillars of Creation” with a new lens. Images taken with the Spitzer Space Telescope uncovered a cloud of hot dust in the vicinity of the Pillars of Creation that one group interpreted to be a shock wave produced by a supernova. The appearance of the cloud suggests a supernova would have destroyed these Pillars of Creation 6000 years ago. Given the distance of roughly 7000 light years to the Pillars of Creation, this would mean that they have actually already been destroyed, but because of the finite speed of light, this destruction is not yet visible on Earth, but should be visible in about 1000 years. However, this interpretation of the hot dust has been disputed by an astronomer uninvolved in the Spitzer observations, who argues that a supernova should have resulted in stronger radio and x-ray radiation than has been observed, and that winds from massive stars could instead have heated the dust. If this is the case, the Pillars of Creation will undergo a more gradual erosion.
Clouds casting thousand-mile shadows when viewed from the International Space Station.
04. A rocket
A rocket leaving Earth’s atmosphere. I like how big our rockets are in person, but how small and insignificant looking they are when compared to the planet and space.
05. Pole Storm
Saturn’s North Pole Storm. Absolutely Mesmerizing. The inner storm is about 2000 km across. The outer hexagon wall is 13,800 km, which is more than the diameter of Earth.
Astronaut Scott Kelly captures a Earth/Moon/Venus/Jupiter alignment from the ISS.
07. Hubble anniversary
Hubble’s 25th anniversary image. There is a bit of science behind this prettiness, I actually have a colleague studying the star cluster in this picture, which is called Westerlund 2 (after an astronomer named Westerlund who cataloged it). It’s about 20,000 light years from us in another spiral arm of the Milky Way, at a more-or-less similar distance from the center. The reason these stars are really interesting to astronomers is they are super young, as one might guess from being right next to the nebula, like only a million or two years old young. That’s nothing for stars like our sun that live billions of years, these guys are babies! Except these stars are particularly hot and bright ones- mainly O stars, the biggest kind of stars, which only live 5-6 million years. So if you’re an O star, you’re through a decent fraction of your lifetime already, and will explode in a firey supernova at the end of that life.
So I always say O stars are the true rock stars of the universe: live fast, shine bright, and die young. Anyway…
So the reason my colleague studies this cluster is it has some of the most massive stars we know of in it- there’s a pair of supermassive stars in a binary (which is awesome because then you can measure the star’s masses- luckily for reasons we don’t know most supermassive stars form in binaries) and one of those clocked in at 80 solar masses (80 times the mass of our sun). That is insane. For perspective, anything over 15 solar masses is already an O star, so we’re talking about a star that is maybe one of a hundred in a galaxy of 100 billion stars. It has a super strong stellar wind though, so was likely much bigger when it formed, and will be maybe “only” 50 solar masses when it dies.
Andromeda’s actual size if it was brighter. Most versions of this size comparison paste the moon (rather poorly) onto an existing picture of the galaxy. But I couldn’t find any the other way round, where the galaxy is pasted onto an existing picture of the moon. I think you get a much more realistic sense of what’s ‘hidden’ in our night sky like this.
The measurement for how large objects appear to us in the sky is apparent diameter (or angular diameter or apparent size). It’s measured in degrees, minutes and seconds. Horizon to horizon is 180º.
The Andromeda Galaxy is 3º across and 1º high from where we stand on Earth. The moon is 30′ or 0.5° so that galaxy is about 6 times bigger than the moon from where we stand. For comparison the sun is about 30′ (which is why total solar eclipses work the way they do).
We measure brightness in magnitude. The (full) moon is -12, Andromeda Galaxy is 3.5. This is a logarithmic scale (each whole step down is twice as bright) so the Andromeda Galaxy is much dimmer than the moon. For comparison: the sun is -26, Venus reaches -4.9, Jupiter -1.6.
Andromeda Galaxy is about 2.5 million light years away so it seems dimmer and smaller to us than the moon which is 1.2 light seconds away.
Pluto’s moon, Charon, at highest resolution yet and in color. Here’s some stuff we know about Charon from this image:
- Charon has a seemingly paradoxical combination of very smooth and near-craterless terrain, paired with a heavily scarred and fractured surface. Huge ravines and canyons that are miles and miles deep, only paralleled by Valles Marineris on Mars, cover the whole surface all the way around, particularly towards the equatorial regions, but some huge fractures stretching towards the poles.
- There are also strangely upwelled looking moated mountains that seem to rise up out of the ground out of nowhere, like a impactor hitting play-doh and rather than tossing that material everywhere it lumped it altogether in one big mountain several thousand feet tall. Or maybe an impact caused a breach in a subsurface liquid reservoir that burst open and turned into a cryovolcano. Any geologists out there an correct me if I’m wrong, but I don’t know of any other examples of this type of formation elsewhere in the solar system. Craters sometimes have central peaks, but nothing this extreme.
- Some huge cataclysmic upheaval must have occurred to leave the surface this torn and scarred. Some ravines are so deep that it’s as if the entire crust layer itself of the small moon was ripped open. The smooth terrain in between suggests potential cryovolcanic activity in its past (perhaps even today), as older terrain would be heavily cratered. It is near unheard of to see such a small object like this have such a young and incredibly diverse surface without any major tidal influences.
- Charon and Pluto are tidally locked with one another, so neither feels any tidal stretching or compressing from the other since they are always the same distance and orientation with respect to each other, unlike, say, Jupiter’s moon Europa, whose active surface is thanks to a interior heated by the changing tidal forces it feels from both Jupiter and it’s fellow large Jovian moons, Io, Ganymede, & Callisto. It boggles the mind as to how such tiny worlds like Pluto and Charon can have such recently renewed surfaces as they do, and will force a lot of established science on the subject to go back to the drawing board to figure out how this is possible. Radioactive potassium or some other source is a possibility (one of the few viable hypotheses that scientists can think of so far), but at this point it’s anyone’s guess.
A Shipwreck under the Milky Way. Photographed by Mikko Lagerstedt
11. Milky Way’s magnetic field
The European Space Agency reports that this image, captured by the Planck spacecraft, is among the first to reveal the shape of the Milky Way’s magnetic field. The image portrays the interaction between interstellar dust in the Milky Way and the structure of our Galaxy’s magnetic field.
12. Untethered spacewalk
Bruce McCandless on the first ever untethered spacewalk, February 7, 1984. He said doing this walk was the most he ever trusted the laws of physics, that he wouldn’t start falling to Earth. It wasn’t as peaceful as he hoped because there were 3 different people talking in his ear the whole time. 1. Reminding him of the basic instructions. 2. Reading his vitals. 3. Another astronaut asking when it was going to be his turn to go. The whole experiment was done with the idea that the shuttle astronauts can go and repair satellites in orbit, without having to capture them. The plan was abandoned after Challenger happened.