Messier 20 and 21 - Astronomy picture of the day - 2018 August 24

Messier 20 and 21 
Image Credit & Copyright: Ignacio Diaz Bobillo

Explanation: The beautiful Trifid Nebula, also known as Messier 20, is easy to find with a small telescope in the nebula rich constellation Sagittarius. About 5,000 light-years away, the colorful study in cosmic contrasts shares this well-composed, nearly 1 degree wide field with open star cluster Messier 21 (bottom right). Trisected by dust lanes the Trifid itself is about 40 light-years across and a mere 300,000 years old. That makes it one of the youngest star forming regions in our sky, with newborn and embryonic stars embedded in its natal dust and gas clouds. Estimates of the distance to open star cluster M21 are similar to M20's, but though they share this gorgeous telescopic skyscape there is no apparent connection between the two. In fact, M21's stars are much older, about 8 million years old.

Comet, Heart and Soul - Astronomy picture of the day - 2018 August 23

Comet, Heart and Soul
Image Credit & Copyright: Juan Carlos Casado (TWAN, Earth and Stars)

Explanation: The greenish coma of comet 21P/Giacobini-Zinner stands out at the left of this telephoto skyscape spanning over 10 degrees toward the northern constellations Cassiopeia and Perseus. Captured on August 17, the periodic comet is the known parent body of the upcoming Draconid meteor shower. Predicted to be at its brightest next month, the comet is actually in the foreground of the rich starfield, only about 4 light-minutes from our fair planet. Giacobini-Zinner should remain too faint for your eye to see though, like the colorful Heart and Soul nebulae near the center of the sensitive digital camera's field of view. But the pair of open star clusters at the right, h and Chi Persei, could just be seen by the unaided eye from dark locations. The Heart and Soul nebulae with their own embedded clusters of young stars a million or so years old, are each over 200 light-years across and 6 to 7 thousand light-years away. They are part of a large, active star forming complex sprawling along the Perseus spiral arm of our Milky Way Galaxy. Also known as the Double Cluster, h and Chi Persei are located at about that same distance. Periodic Giacobini-Zinner was visited by a spacecraft from Earth when the repurposed International Cometary Explorer passed through its tail in September 1985.

Asteroid Ryugu from Hayabusa2 - Astronomy picture of the day - 2018 August 22

Asteroid Ryugu from Hayabusa2 
Image Credit & Copyright: ISAS, JAXA,

Explanation: This big space diamond has an estimated value of over 80 billion dollars. It's only diamond in shape, though -- asteroid 162173 Ryugu is thought to be composed of mostly nickel and iron. Asteroids like Ryugu are interesting for several reasons, perhaps foremost because they are near the Earth and might, one day in the far future, pose an impact threat. In the nearer term, Ryugu is interesting because it may be possible to send future spacecraft there to mine it, thus providing humanity with a new source of valuable metals. Scientifically, Ryugu is interesting because it carries information about how our Solar System formed billions of years ago, and why its orbit takes it so closeto Earth. Japan's robotic spacecraft Hayabusa2 just arrived at this one-kilometer wide asteroid in late June. The featured image shows surface structures unknown before spacecraft Hayabusa2's arrival, including rock fields and craters. Within the next three months, Hayabusa2 is scheduled to unleash several probes, some that will land on Ryugu and hop around, while Hayabusa2 itself will mine just a little bit of the asteroid for return to Earth.

Glowing Elements in the Soul Nebula - Astronomy picture of the day - 2018 August 21

Glowing Elements in the Soul Nebula 
Image Credit & Copyright: Jesús M.Vargas & Maritxu Poyal

Explanation: Stars are forming in the Soul of the Queen of Aethopia. More specifically, a large star forming region called the Soul Nebula (IC 1898) can be found in the direction of the constellation Cassiopeia, who Greek mythology credits as the vain wife of a King who long ago ruled lands surrounding the upper Nile river. The Soul Nebula houses several open clusters of stars, a large radio source known as W5, and huge evacuated bubbles formed by the winds of young massive stars. Located about 6,500 light years away, the Soul Nebula spans about 100 light years and is usually imaged next to its celestial neighbor the Heart Nebula (IC 1805). The featured image is a composite of three exposures in different colors: red as emitted by hydrogen gas, yellow as emitted by sulfur, and blue as emitted by oxygen.

Active Prominences on a Quiet Sun - Astronomy picture of the day - 2018 August 20

Active Prominences on a Quiet Sun  Image Credit & Copyright: Alan Friedman (Averted Imagination)

Explanation: Why is the Sun so quiet? As the Sun enters into a period of time known as a Solar Minimum, it is, as expected, showing fewer sunspots and active regions than usual. The quietness is somewhat unsettling, though, as so far this year, most days show no sunspots at all. In contrast, from 2011 - 2015, during Solar Maximum, the Sun displayed spots just about every day. Maxima and minima occur on an 11-year cycle, with the last Solar Minimum being the most quiet in a century. Will this current Solar Minimum go even deeper? Even though the Sun's activity affects the Earth and its surroundings, no one knows for sure what the Sun will do next, and the physics behind the processes remain an active topic of research. The featured image was taken three weeks ago and shows that our Sun is busy even on a quiet day. Prominences of hot plasma, some larger than the Earth, dance continually and are most easily visible over the edge.

Asperitas Clouds Over New Zealand - Astronomy picture of the day - 2018 August 19

Asperitas Clouds Over New Zealand 
Image Credit & Copyright: Witta Priester

Explanation: What kind of clouds are these? Although their cause is presently unknown, such unusual atmospheric structures, as menacing as they might seem, do not appear to be harbingers of meteorological doom. Formally recognized as a distinct cloud type only last year, Asperitas clouds can be stunning in appearance, unusual in occurrence, and are relatively unstudied. Whereas most low cloud decks are flat bottomed, asperitas clouds appear to have significant vertical structure underneath. Speculation therefore holds that asperitas clouds might be related to lenticular clouds that form near mountains, or mammatus clouds associated with thunderstorms, or perhaps a foehn wind -- a type of dry downward wind that flows off mountains. Such a wind called the Canterbury arch streams toward the east coast of New Zealand's South Island. The featured image, taken above Hanmer Springs in Canterbury, New Zealand, in 2005, shows great detail partly because sunlight illuminates the undulating clouds from the side.

Seeing Titan - Astronomy picture of the day - 2018 August 18

Seeing Titan 
Image Credit: VIMS Team, U. Arizona, ESA, NASA

Explanation: Shrouded in a thick atmosphere, Saturn's largest moon Titan really is hard to see. Small particles suspended in the upper atmosphere cause an almost impenetrable haze, strongly scattering light at visible wavelengths and hiding Titan's surface features from prying eyes. But Titan's surface is better imaged at infrared wavelengths where scattering is weaker and atmospheric absorption is reduced. Arrayed around this centered visible light image of Titan are some of the clearest global infrared views of the tantalizing moon so far. In false color, the six panels present a consistent processing of 13 years of infrared image data from the Visual and Infrared Mapping Spectrometer (VIMS) on board the Cassini spacecraft. They offer a stunning comparison with Cassini's visible light view.

Une réussite : Le traitement extracorporel du cancer - Médecine

Une équipe italienne a traité un patient atteint d'un cancer du foie très avancé grâce à une méthode inédite. Les chercheurs ont retiré l'organe, l'ont traité par irradiation avant de le réimplanter. Plusieurs mois après l'opération, l'homme qu'on disait condamné va bien. Cette technique pourra-t-elle demain être étendue à tous les organes transplantables : reins, poumons, pancréas… ?

Pour la première fois au monde, un cancer a été traité en retirant l'organe du corps, en lui administrant un traitement par radiothérapie et en le réimplantant. Cette opération extracorporelle a permis aux médecins d'administrer de fortes doses de radiations aux différentes tumeurs disséminées sur le foie, sans affecter les organes environnants.

Un cas "désespéré"

Agé de 48 ans, le patient était jugé comme étant dans une situation désespérée. Suite au diagnostic d'un cancer du colon, une partie de l'intestin lui avait été enlevé en 2000. Mais le cancer avait eu le temps d'atteindre un autre organe : le foie. Des scanners révélèrent pas moins de 14 tumeurs sur l'organe et, suite à l'opération, de nombreuses autres furent identifiées. De tels cancers sont généralement très difficiles à traiter par les moyens thérapeutiques conventionnels. Le pronostic avancé ne dépassait pas trois à quatre mois d'espérance de vie…

Un an après l'opération qui a duré 21 heures, l'homme est en bonne santé.
Cette nouvelle technique baptisée TAORMINA devrait bientôt concerner d'autres patients.

"Enthousiaste au vu des premiers résultats, le Dr Pirelli déclare dès maintenant que ce type d'opération permet le traitement intégral de l'organe malade et peut être étendu à tous les organes transplantables : reins, pancréas, poumons…".

Doctissimo

Perseid Fireball and Persistent Train - Astronomy picture of the day - 2018 August 17

Perseid Fireball and Persistent Train 
Image Credit & Copyright: Petr Horálek

Explanation: Before local midnight on August 12, this brilliant Perseid meteor flashed above the Poloniny Dark Sky Park, Slovakia, planet Earth. Streaking beside the summer Milky Way, its initial color is likely due to the shower meteor's characteristically high speed. Moving at about 60 kilometers per second, Perseid meteors can excite green emission from oxygen atoms while passing through the thin atmosphere at high altitudes. Also characteristic of bright meteors, this Perseid left a lingering visible trail known as a persistent train, wafting in the upper atmosphere. Its development is followed in the inset frames, exposures separated by one minute and shown at the scale of the original image. Compared to the brief flash of the meteor, the wraith-like trail really is persistent. After an hour faint remnants of this one could still be traced, expanding to over 80 degrees on the sky.

Parker vs Perseid - Astronomy picture of the day - 2018 August 16

Parker vs Perseid 
Image Credit & Copyright: Derek Demeter (Emil Buehler Planetarium)

Explanation: The brief flash of a bright Perseid meteor streaks across the upper right in this composited series of exposures made early Sunday morning near the peak of the annual Perseid meteor shower. Set up about two miles from Space Launch Complex 37 at Cape Canaveral Air Force Station, the photographer also captured the four minute long trail of a Delta IV Heavy rocket carrying the Parker Solar Probe into the dark morning sky. Perseid meteors aren't slow. The grains of dust from periodic comet Swift-Tuttle vaporize as they plow through Earth's upper atmosphere at about 60 kilometers per second (133,000 mph). On its way to seven gravity-assist flybys of Venus over its seven year mission, the Parker Solar Probe's closest approach to the Sun will steadily decrease, finally reaching a distance of 6.1 million kilometers (3.8 million miles). That's about 1/8 the distance between Mercury and the Sun, and within the solar corona, the Sun's tenuous outer atmosphere. By then it will be traveling roughly 190 kilometers per second (430,000 mph) with respect to the Sun, a record for fastest spacecraft from planet Earth.