Cave with Aurora Skylight
Image Credit & Copyright: Ingólfur Bjargmundsson
Explanation: Yes, but have you ever seen aurora from a cave? To capture this fascinating juxtaposition between below and above, astrophotographer Bjargmundsson spent much of a night alone in the kilometer-longRaufarhólshellir lava cave in Iceland during late March. There, he took separate images of three parts of the cave using a strobe for illumination. He also took a deep image of the sky to capture faint aurora, and digitally combined the four images later. The 4600-year old lava tube has several skylights under which stone rubble and snow have accumulated. Oh — the person standing on each mound — it’s the artist.
45 Years Ago Today: First Humans Land on the Moon
Apollo 11 was the spaceflight that landed the first humans on the Moon, Americans Neil Armstrong and Buzz Aldrin, on July 20, 1969, at 20:18 UTC. Armstrong became the first to step onto the lunar surface six hours later on July 21 at 02:56 UTC. Armstrong spent about two and a half hours outside the spacecraft, Aldrin slightly less, and together they collected 47.5 pounds (21.5 kg) of lunar material for return to Earth. A third member of the mission, Michael Collins, piloted the command spacecraft alone in lunar orbit until Armstrong and Aldrin returned to it just under a day later for the trip back to Earth.
Launched by a Saturn V rocket from Kennedy Space Center in Merritt Island, Florida, on July 16, Apollo 11 was the fifth manned mission of NASA’s Apollo program. The Apollo spacecraft had three parts: a Command Module (CM) with a cabin for the three astronauts, and the only part that landed back on Earth; a Service Module (SM), which supported the Command Module with propulsion, electrical power, oxygen, and water; and a Lunar Module (LM) for landing on the Moon. After being sent toward the Moon by the Saturn V’s upper stage, the astronauts separated the spacecraft from it and traveled for three days until they entered into lunar orbit. Armstrong and Aldrin then moved into the Lunar Module and landed in the Sea of Tranquility. They stayed a total of about 21½ hours on the lunar surface. After lifting off in the upper part of the Lunar Module and rejoining Collins in the Command Module, they returned to Earth and landed in the Pacific Ocean on July 24.
Broadcast on live TV to a world-wide audience, Armstrong stepped onto the lunar surface and described the event as “one small step for man, one giant leap for mankind.”
The Flame Extinguishment - 2 (FLEX-2) experiment is the second experiment to fly on the ISS which uses small droplets of fuel to study the special spherical characteristics of burning fuel droplets in space. The FLEX-2 experiment studies how quickly fuel burns, the conditions required for soot to form, and how mixtures of fuels evaporate before burning. Understanding how fuels burn in microgravity could improve the efficiency of fuel mixtures used for interplanetary missions by reducing cost and weight. It could also lead to improved safety measures for manned spacecraft.
- More information: here
Credit: Reid Wiseman/NASA
claudette: Surface of Mars, photographed by Mars Express, 10 April 2008.
On the Vastitas Borealis. Believe this image runs about 660 km from 79°N 55°E to 68°N 62°E.
Composite of 3 visible light images for colour and one monochrome for detail. Colour balance is not naturalistic.
Image credit: ESA. Composite: AgeOfDestruction.
I think we can all relate!
I’ve actually never been disappointed by observations. Sure I’ve seen loads of gorgeous photos and all, and it would be cool to see that stuff and all. But I remember when a few months back I saw the Orion Nebula for the first time it was just this blurry bluish thing and it was still pretty damn awesome. I mean I was just looking at a nebula. It was there. I was directly looking at it through a telescope. It wasn’t just a picture anymore. How AWESOME is that? So sure, don’t expect to see the same stuff you’ll see in heavily processed photos, but don’t doubt for an instant that the reality will still be really freaking cool.
A NASA probe recently spotted the dazzling Pan-STARRS comet as it hurtled through space against the backdrop of a distant galaxy. Learn more!
The world’s highest resolution visualization system, created by NASA
Way back in 2010, Gliese 581g made waves as “the Goldilocks planet”. It was the first planet scientists found within the habitable zone—the region around a star where it’s not too hot and not too cold for liquid water to endure on a planet’s surface. But after the initial excitement about finding a planet that could potentially support life, some scientists started to seriously doubt whether Gliese 581g was really there, because the signal was weak. Despite all the debate, lots of astronomers listed Gliese 581g as the top spot to look for alien life.
Now, new research says that Gliese 581g doesn’t actually exist.
Astronomers can’t actually see the planets in the Gliese 581 star system. Instead, they detected the planetary candidates by monitoring the star’s light. As a planet orbits, its gravity tugs on the star and distorts the light coming off it, changing the wavelengths and thus the color of light that reaches telescopes here on Earth. (Here’s a longer explanation of the radial velocity technique, if you’re interested.) The problem is that the star also moves, and as it rotates its sunspots and other solar activity also distort the light coming off of it.
Until now, scientists didn’t know how fast the Gliese 581 star spins around. Now they know it makes a complete rotation approximately every 130 days. With that new information, they were able to go back into the data and take out the signals coming from the star’s movements. And when they did that, the signals for Gliese 581g disappeared. Same goes for Gliese 581d, which had also been an exciting and potentially habitable planet. But the technique did confirm that three other planets within the Gliese 581 star system are indeed really there.
Luckily, the 977 exoplanets discovered by the Kepler Space Telescope are probably not in jeopardy. Rather than measuring light wavelengths, Kepler finds exoplanets by looking for the shadows create as they pass in front of stars, so it’s not as susceptible to stellar rotation noise.
The other good news is that the new technique is handy for confirming exoplanets’ existence (not just ruling them out), and will hopefully make it easier to spot more Earth-sized planets. “For very low-mass planets like Earth, their Doppler signals will be smaller than those created by stellar activity for nearly all stars,” says astronomer Paul Robertson from Penn State University, the lead author on the new study. “It is necessary to remove the stellar activity signals in order to find these very exciting planets.”
The new paper appears today in Science.
These “lines” that you see are actually called diffraction spikes. In most images you will see 4 diffraction spikes, but a star/astronomical object is not limited to having only 4. an example of diffraction spikes:
Diffraction spikes are not actually a property of stars and astronomical objects. These lines of light are a result of the way reflector telescopes are built. Images of stars only have lines because of the structure of the telescopes that imaged them.
In the above diagram we see how a reflector telescope works. This Newtonian style Reflector telescope reflects light onto a large concave mirror in the back of the telescope. The light from that back mirror is focused onto a smaller flat mirror in the center of the telescope and then into the viewer’s eye. The flat mirror is what indirectly causes the diffraction spikes because it must be centered with support beams.
These support beams (labeled 3 in the above image) cause the diffraction patter. The reason we see a central band of light in four directions around the star can be explained with Young’s double slit experiment. (click here if you want to see the math) Math aside, light that passes around a thin wire (in this case the supports) will create a very specific pattern:
The constructive and destructive interference of the light waves will cause a single band of intense light where the support beam was (with some smaller bands father out but those are negligible in this case).
And that’s why you see those “lines” (which are known as diffraction spikes) when you look at telescope images of stars! Thanks for the great ask! DFTBA