planets
A once in a lifetime event visible every 75-76 years, Halleys comet returned in 1986. Halley is the only short-period comet that is clearly visible to the naked eye from Earth. It has been documented since 240 BC.
An image of the North polar region of Jupiter.
Taken by NASA’s spacecraft Juno.
Starry Night Castle. Credit & Copyright: P-M Hedén
The Pleiades star cluster seems to lie just beyond the trees above a dark castle tower in this dramatic view. This starry sky also features bright star Aldebaran below the Pleiades and a small, faint, fuzzy cloud otherwise known as Comet Holmes near picture center at the top of the field. Starry Night Castle might be an appropriate name for the medieval castle ruin in the foreground. But its traditional name is Mörby Castle, found north of Stockholm, near lake Skedviken in Norrtälje, Sweden.
Great collection of astronomical articles and pictures
NASA’s Cassini spacecraft, which orbits Saturn, took a picture of Earth from between Saturn’s rings — with Earth’s moon at its side.
Captured at 1:41 a.m. Eastern on April 12, 2017, the spacecraft was 870 million miles away from its home planet when it took the image.
Earth is seen as a tiny bright speck in the center of the picture. Upon cropping and zooming in, its moon can be seen to the left as an even smaller dot. The photograph, captured by the Imaging Science Subsystem, doesn’t clearly show which part of Earth is facing the ringed planet at the time the picture was taken, but NASA has revealed it is the southern Atlantic Ocean. Read more (4/21/17)
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From the original iPhone to the iPhone 6, here’s how much the camera has evolved.
A liquid oxygen tank confidence article for NASA’s new rocket, the Space Launch System, completes final welding on the Vertical Assembly Center at Michoud Assembly Facility in New Orleans.
A liquid oxygen tank confidence article for NASA’s new rocket, the Space Launch System, completes final welding on the Vertical Assembly Center at Michoud Assembly Facility in New Orleans.
“Cassini provided scientists with a wealth of data about Enceladus’ surface and the composition of its powerful plumes. This data showed evidence of a deep saltwater ocean with an energy source beneath Enceladus’ surface. The presence of water, warmth, and organic molecules are the necessary requirements for sustaining life as we know it. Water is proven to exist, while the tidal forces from Saturn provide the necessary heat. Based on observations of other bodies in the Solar System, Enceladus likely contains the raw ingredients for life as well. The suspected existence of all three hints at the possible presence of the precursors to amino acids in this vast subsurface ocean. Should we find extraterrestrial life on Enceladus – or in the geyser-like plumes erupting into space – the implications are almost incomprehensible.”
When you think about life beyond Earth, you likely think of it occurring on a somewhat Earth-like planet. A rocky world, with either a past or present liquid ocean atop the surface, seems ideal. But that might not even be where life on Earth originated! Deep beneath the Earth’s surface, geologically active hydrothermal vents currently support diverse colonies of life without any energy from the Sun. Saturn’s icy moon, Enceladus, has a subsurface ocean unlike any other world we’ve yet discovered. The tidal forces of Saturn itself provide the necessary heat, and also create cracks in the Enceladean surface, enabling massive geysers. This subsurface ocean rises hundreds of kilometers high, regularly resurfaces the world with a coat of fresh ice, and even creates the E-ring of Saturn. But most spectacularly, it may house actively living organisms, and could be the next-best world for life, after Earth, in the Solar System today.
Come get the full story on Enceladus, and welcome Starts With A Bang’s newest contributor, the remarkable Jesse Shanahan!
Jupiter. The king of our solar system. It might not be the greatest picture ever taken of Jupiter but at least I get to call it mine! You can even make out Jupiter’s great red spot, a storm so big that it could engulf Earth 3 times over!
“Quantum cryptography uses the quantum properties of photons to guarantee perfect secrecy. But one of its lesser known limitations is that it only works if Alice and Bob are perfectly aligned so that they can carry out well-defined polarization measurements on the photons as they arrive. Physicists say that Alice and Bob must share the same reference frame. That’s OK if Alice and Bob are in their own ground-based labs, but it’s a problem in many other applications, such as ground-to-satellite communications or even in chip-to-chip communications, because it’s hard to keep chips still over distances of the order of the wavelength of light. Now a group of UK physicists have developed a way of doing quantum cryptography without sharing a reference frame. The trick is to use entangled triplets of photons, so-called qutrits, rather than entangled pairs. This solves the problem by embedding it in an extra abstract dimension, which is independent of space. So, as long as both Alice and Bob know the way in which all these abstract dimensions are related, the third provides a reference against which measurements of the other two can be made. That allows Alice and Bob to make any measurements they need without having to agree ahead of time on a frame of reference. That could be an important advance enabling the widespread use of quantum cryptography.”