NASA's Solar Dynamics Observatory is getting some really amazing shots of the Sun, including this 200,000 mile-long solar eruption that left a huge canyon on the surface of the Sun:
Different wavelengths help capture different aspect of events in the corona. The red images shown in the movie help highlight plasma at temperatures of 90,000° F and are good for observing filaments as they form and erupt. The yellow images, showing temperatures at 1,000,000° F, are useful for observing material coursing along the sun's magnetic field lines, seen in the movie as an arcade of loops across the area of the eruption. The browner images at the beginning of the movie show material at temperatures of 1,800,000° F, and it is here where the canyon of fire imagery is most obvious.
The level of detail shown is incredible. (via @DavidGrann)
Turning the Sun into a giant radio telescope through gravitational lensing will take some work, but it is possible.
An Italian space scientist, Claudio Maccone, believes that gravitational lensing could be used for something even more extraordinary: searching for radio signals from alien civilizations. Maccone wants to use the sun as a gravitational lens to make an extraordinarily sensitive radio telescope. He did not invent the idea, which he calls FOCAL, but he has studied it more deeply than anyone else. A radio telescope at a gravitational focal point of the sun would be incredibly sensitive. (Unlike an optical lens, a gravitational lens actually has many focal points that lie along a straight line, called a focal line; imagine a line running through an observer, the center of the lens, and the target.) For one particular frequency that has been proposed as a channel for interstellar communication, a telescope would amplify the signal by a factor of 1.3 quadrillion.
The center of the Sun is extremely dense, and a photon can only travel a tiny distance before running into another hydrogen nucleus. It gets absorbed by that nucleus and the re-emitted in a random direction. If that direction is back towards the center of the Sun, the photon has lost ground! It will get re-absorbed, and then re-emitted, over and over, trillions of times.
This is from 1997, so that figure might have been revised a bit (anyone have updated numbers?) but still, that's incredible. (via hacker news)
In complete defiance of its parents, NASA's Solar Dynamics Observatory has stared directly at the Sun for the past three years. Here's a video of those three years made from still images taken by the SDO.
During the course of the video, the sun subtly increases and decreases in apparent size. This is because the distance between the SDO spacecraft and the sun varies over time. The image is, however, remarkably consistent and stable despite the fact that SDO orbits the Earth at 6,876 miles per hour and the Earth orbits the sun at 67,062 miles per hour.
The video notes say the animation uses two images per day...it would be nice to see the same animation with a higher frame rate. (via ★interesting)
Since the Sun moves relative to the other stars around it at about 45,000 miles/hr, if you change the frame of reference from the Sun to the surrounding stellar system, you get planetary motion that looks something like this:
I would take this video with a grain of salt though, especially when it says things like "the Sun is like a comet, dragging the planets in its wake"...the planets don't lag behind the Sun. Better to think of the thing as a conceptual schematic: resembling reality but not really accurate. (via @pieratt)
Update: There's a new version of the video that addresses some of the concerns raised about the first video:
However, there's a problem with it: It's wrong. And not just superficially; it's deeply wrong, based on a very wrong premise. While there are some useful visualizations in it, I caution people to take it with a galaxy-sized grain of salt.
On Dec 13, 2006, the sun itself provided a crucial clue, when a solar flare sent a stream of particles and radiation toward Earth. Purdue nuclear engineer Jere Jenkins, while measuring the decay rate of manganese-54, a short-lived isotope used in medical diagnostics, noticed that the rate dropped slightly during the flare, a decrease that started about a day and a half before the flare.
If this apparent relationship between flares and decay rates proves true, it could lead to a method of predicting solar flares prior to their occurrence, which could help prevent damage to satellites and electric grids, as well as save the lives of astronauts in space.
The decay-rate aberrations that Jenkins noticed occurred during the middle of the night in Indiana -- meaning that something produced by the sun had traveled all the way through the Earth to reach Jenkins' detectors. What could the flare send forth that could have such an effect?
Jenkins and Fischbach guessed that the culprits in this bit of decay-rate mischief were probably solar neutrinos, the almost massless particles famous for flying at nearly the speed of light through the physical world -- humans, rocks, oceans or planets -- with virtually no interaction with anything.
Maybe the science part of 2012 wasn't so far-fetched after all. (No, not really.)
Within hours, telegraph wires in both the United States and Europe spontaneously shorted out, causing numerous fires, while the Northern Lights, solar-induced phenomena more closely associated with regions near Earth's North Pole, were documented as far south as Rome, Havana and Hawaii, with similar effects at the South Pole.
The southern wall of the Grand Concourse, facing 42nd Street, has semicircular grills high up, with small curlicued spaces like those in a leafy tree. Many of those spaces act like the aperture of a pinhole camera, reflecting an image of the sun that, when it reaches the floor, will be 8 to 12 inches wide. The smaller grill spaces will produce dimmer but sharper solar images on your paper.
A solar furnace is a structure used to harness the rays of the sun in order to produce high temperatures. This is achieved by using a curved mirror (or an array of mirrors) acting as a parabolic reflector to concentrate light (Insolation) on to a focal point. The temperature at the focal point may reach up to 3,000 degrees Celsius, and this heat can be used to generate electricity, melt steel or make hydrogen fuel.
DANGER! This device is extremely dangerous. It should not be constructed or operated by anyone who does not observe proper safety precautions. It will instantly destroy flesh. It will melt metals, ceramics, and most any other material. Always wear welding goggles when operating this device! DO NOT leave this device unattended.
This DIY solar furnace is capable of melting brick (!!) and will "boil" a quarter in ~25 seconds.
When Marcellus withdrew them [his ships] a bow-shot, the old man [Archimedes] constructed a kind of hexagonal mirror, and at an interval proportionate to the size of the mirror he set similar small mirrors with four edges, moved by links and by a form of hinge, and made it the centre of the sun's beams--its noon-tide beam, whether in summer or in mid-winter. Afterwards, when the beams were reflected in the mirror, a fearful kindling of fire was raised in the ships, and at the distance of a bow-shot he turned them into ashes. In this way did the old man prevail over Marcellus with his weapons.