The Earth Breathes, and It Is Beautiful
Using NASA’s latest high-resolution satellite imagery of Earth, datavisualization expert John Nelson has created a pair of captivating animations that track seasonal transformations on the blue marble we call home.
NASA scientists have just confirmed an entirely new category of planet just 40 light years away: A world with a diameter 2.7 times larger than Earth that’s covered almost entirely in water. “If you want to describe in one sentence what this planet is, it’s a big, hot ocean.”
The infrared eye of the Helix
700 light years away in the constellation of Aquarius lies the Helix nebula, the expanding shell of gas from a dying star. This nebula is huge, 2.5 light years across, and so close that it’s roughly the same size as the full Moon in the sky!
Spitzer’s ability to see in the infrared becomes critical here; even though this is a well-studied nebula, this view of IR light invisible to our eyes reveals something never seen before in the Helix: a circular disk of dust surrounding the star (seen as the red circle immediately outside the star). Astronomers think this dust may have come from trillions of comets that orbited the star; they would’ve been vaporized when it expanded into a red giant.
The tendrils on the outer ring ironically look like comets but are actually caused when the hot, fast stellar wind from the central star caught up and collided with a slower, denser wind ejected earlier by the star. The gas fragmented in the collision, forming clumps, which erode away and blow off those long tails as the hot wind eats into them. To give you a sense of scale, each one of those clumps is bigger than our solar system, and the tails are a hundred billion kilometers long!
Twenty Four Hour View of the Sky
After wondering for some time whether it was possible to image the sky from one morning to the next where I live in Athens Greece, I decided to give it a try. After hours of planning and preparation, and a full day of shooting, the image above is the result of this labor of love. It took me about 12 hours to pull together and process a single image that included over 500 star trails, 35 shots of the Sun and 25 landscape pictures. My plan was to make the image on the day of the solstice (December 21) when the Sun’s stay in the sky was short (in the Northern Hemisphere) and the star trail durations were long. Of course, trying to find clear weather for a given 24-hour period is not an easy chore. However, I was patient, and the weather eventually cooperated (on December 30-31, 2010). I had to stay at the same place for approximately 30 hours. In addition, I was on location 2-3 hours before sunrise in order to make the preparations and test shooting. I also needed to stay an extra 2-3 hours the second day so as to shoot part of the Sun’s sequence that I lost the first morning due to clouds. I chose Sounion (Temple of Poseidon) as the setting for this project. Click on image to see labels.
I began the shooting the morning of December 30, 2010, taking photos with my camera on a tripod facing east. The day portion of this shoot is composed of a dozen shots covering the landscape from east to west as well as the Sun’s course across the sky, from sunrise to sunset. I recorded the Sun’s position exactly every 15 minutes using an intervalometer, with an astrosolar filter adjusted to the camera lens. In one of the shots, when the Sun was near its maximum altitude, I removed the filter in order to capture a more dramatic shot that showed the Sun’s “glare.” After sunset, I took various shots with the camera facing west-northwest in order to achieve a more smooth transition from the day portion to the night portion of the image. The night portion is also composed of a dozen landscape shots but this time from west to east. After the transition” shots, I took a short star trail sequence of approximately half an hour duration, with the camera facing northwest. At 7:30, I turned the camera to the north and started taking the “all-night” star trail shots — lasting almost 11 hours. After accomplishing this, I then turned the camera to northeast and shot another short half an hour star trail sequence, and then finally, with the camera now facing east-northeast, I took a series of night-to-day transition shots.
Dimitar Sasselov: How we found hundreds of potential Earth-like planets
Astronomer Dimitar Sasselov and his colleagues search for Earth-like planets that may, someday, help us answer centuries-old questions about the origin and existence of biological life elsewhere (and on Earth). Preliminary results show that they have found 706 “candidates” — some of which further research may prove to be planets with Earth-like geochemical characteristics.
Video: New Space Telescope Delivers First Mind-Blowing Video of the Sun (Wired Science)
In the video embedded above, we see a solar prominence that erupted March 30. Below, we can see the whole star at the time of the prominence, in the extreme ultraviolet part of the spectrum. Reds map to relatively cool temperatures of around 100,000 degrees Fahrenheit (60,000 kelvins), while blues and greens represent hotter regions of more than 1.8 million degrees Fahrenheit (1,000,000 kelvins).
On this day of April in 1533, Galileo stood trial before the Roman Inquisition, to defend the publication of his book Dialogue Concerning the Two Chief World Systems (1632).
It is commonly thought that Galileo was called to defend his scientific beliefs before the Church, who insisted on their own version of the universe. But the purpose of the trial was more complex than that, going back 17 years, to a technicality that occurred the first time that Galileo was officially chastised by the Church. The question was whether he was ordered to stop publishing or teaching anything about a Copernican view of the universe, or whether he was told that he could present it as a theory but not the absolute truth.
And really, it started 90 years earlier, when the Polish astronomer Nicolaus Copernicus published On the Revolutions of the Celestial Spheres (1543), laying out his revolutionary theory: that the earth and other celestial objects rotate around the sun, which is the fixed center of the universe. It was completely at odds with the accepted understanding — legitimized by the Church — that the Earth was at the center. There was a small stir, but Copernicus died at the same time he published his book, and his views were not particularly well publicized and sank into relative obscurity for decades.
But hearing those views from someone like Galileo was another story. Galileo was already famous, a respected scientist and lecturer, years before his involvement with any sort of controversial theory of the universe. After giving up the idea to become a monk, which his father opposed, he studied mathematics and medicine (his father’s choice), but was more interested in math. He was one of the first scientists to show that math could be used to explain the laws of nature, and he used that understanding to conduct breakthrough experiments, including his work on accelerating objects. The story that he dropped cannon balls out of the Leaning Tower of Pisa is probably apocryphal, but he did show that falling objects accelerate at a uniform rate, and that this is true regardless of their weight.
At some point Galileo did become interested in the theory of the universe expressed by Copernicus, and then he discovered something that he thought would prove the theory beyond question: the telescope. A Dutch eyeglass maker is credited with inventing it in 1608, and as soon as he heard about it, Galileo set one up himself, and became the first person to use it to observe the sky. He deduced that the moon was illuminated by a reflection of the sun on the Earth, he saw that Jupiter was orbited by moons, and he studied Venus and realized that the only explanation for its changing phases was that it orbited the sun. He thought that, finally, no one could disagree that the planets orbited the sun, so he started talking openly about his ideas. He wrote and lectured for the educated public, figuring that they were a more receptive audience than scholars.
But of course people did disagree: The Church claimed it was at odds with the Bible, particularly a verse in the Book of Joshua that describes God stopping the sun in the sky, and one in Psalms that says Earth was put on its foundations and would not move. Galileo responded publicly by explaining that the truth of the Bible was not always literal, that it used metaphorical imagery. He wrote: “I do not feel obliged to believe that the same God who has endowed us with senses, reason and intellect has intended us to forego their use and by some other means to give us knowledge which we can attain by them. He would not require us to deny sense and reason in physical matters which are set before our eyes and minds by direct experience or necessary demonstrations.”
And on this day of April in 1533, Galileo was called before the Inquisition to be questioned. They did not give him a chance to defend his view of the universe, nor in fact did they argue with his beliefs at all. Instead, their argument centered on the first time Galileo had been officially reprimanded, 17 years earlier. Galileo was interrogated by the full Inquisition again on April 30th, and he offered to write a sequel in which he argued against Copernicusm. This was not good enough. Weeks later, on June 16th, the pope decreed: “Galileo being interrogated on his intention, even with the threat of torture … he is to abjure in a plenary session of the Congregation of the Holy Office, then is to be condemned to imprisonment at the pleasure of the Holy Congregation, and ordered not to treat further, in whatever manner, either in words or in writing, on the mobility of the Earth and the stability of the Sun; otherwise he will incur the penalties of relapse. The book entitled Dialogue of Galileo Galilei the Lincean is to be prohibited.”
Eventually, he was allowed to return home under house arrest, where he became blind a few years later, and died in 1642. In 1718, the Church lifted its ban on Galileo’s work, with the exception of theDialogues, which was banned until 1822.