Astronomy Picture of the Day: January 21st, 2003
In the vast Orion Molecular Cloud complex, several bright blue nebulas are particularly apparent. Pictured above are two of the most prominent reflection nebulas - dust clouds lit by the reflecting light of bright embedded stars. The more famous nebula is M78, on the upper right, cataloged over 200 years ago. On the lower left is the lesser known NGC 2071. Astronomers continue to study these reflection nebulas to better understand how interior stars form. The Orion complex lies about 1500 light-years distant, contains the Orion and Horsehead nebulas, and covers much of the constellation of Orion.
Credit: Daniel Verschatse (Antilhue Obs.)
Launched on Feb. 11, 2010, the Solar Dynamics Observatory, or SDO, is the most advanced spacecraft ever designed to study the sun. During its five-year mission, it will examine the sun’s atmosphere, magnetic field and also provide a better understanding of the role the sun plays in Earth’s atmospheric chemistry and climate. SDO provides images with resolution 8 times better than high-definition television and returns more than a terabyte of data each day.
On June 5 2012, SDO collected images of the rarest predictable solar event—the transit of Venus across the face of the sun. This event happens in pairs eight years apart that are separated from each other by 105 or 121 years. The last transit was in 2004 and the next will not happen until 2117.
Messier Monday: The Most Elusive Messier Globular, M55
"Because what you’re looking at isn’t just a faint, diffuse cluster of stars, these are stars that date back to some of the earliest times in the history of our galaxy! Our Sun contains lots of heavy elements: carbon, oxygen, silicon, sulphur, iron, and so on, and it’s the abundance of those heavy elements that allowed rocky planets to form around it. Stars that formed longer ago, and in regions that had fewer generations of stars live-and-die to enrich the interstellar medium, tend to be poorer in these heavy elements, and give us a glimpse of the stars that formed when the Universe was much younger.
Globular clusters tend to have older stars, but Messier 55 has just 1.1% of the heavy elements found in the Sun, one of the most metal-poor globulars known to exist!”
Even though Messier knew about this object since the 1750s, and started looking for it in the 60s, it wasn’t until 1778 that he finally found it. Sometimes, the hard work you put in makes the discovery all the more rewarding!
Researchers Make Hydrogen Fuel Sans Rare Metals
The profusion of tiny bubbles escaping from the electrodes as soon as the solar cells are exposed to light say it better than words ever could: the combination of sun and water paves a promising and effervescent way for developing the energy of the future.
The journal Science published the latest development in Michael Grätzel’s laboratory at EPFL: producing hydrogen fuel from sunlight and water. By combining a pair of solar cells made with a mineral called perovskite and low cost electrodes, scientists have obtained a 12.3 percent conversion efficiency from solar energy to hydrogen, a record using earth-abundant materials as opposed to rare metals.
Read more: http://www.laboratoryequipment.com/videos/2014/09/researchers-make-hydrogen-fuel-sans-rare-metals
Apollo 16 Command Module after Splashdown in April 1972
A different perspective on a spaceship returning to Earth: Apollo 16 upside down in the water.
Usually, most splash-down shots show the capsule bobbing on the water, surrounded by its flotation collar. However, the capsules often became inverted once hitting the water, posing a danger to vehicle and crew.
Shortly after jettisoning the parachutes, three air bags would deploy at the top of the capsule, righting it in the water until the collar could be attached by rescue divers.
"Electrified Territory" The MMC Yardmaster’s tower was the perfect place for a front row seat to the ballet of intense lightning that followed up a thunderstorm. Huge bolts reach from the clouds down to the sky scrapers of Jersey City and New York. (via RailPictures.Net Photo: NJTR 4206 NJ Transit EMD GP40PH-2 at Kearny, New Jersey by Michael William Sullivan)
Unusual rocks near Pahrump Hills on Mars
How did these Martian rocks form? As the robotic Curiosity rover has approached Pahrump Hills on Mars, it has seen an interesting and textured landscape dotted by some unusual rocks. The featured image shows a curiously round rock spanning about two centimeters across. Seemingly a larger version of numerous spherules dubbed blueberries found by the Opportunity rover on Mars in 2004, what caused this roundness remains unknown. Possibilities include frequent tumbling in flowing water, sprayed molten rock in a volcanic eruption, or a concretion mechanism. The inset image, taken a few days later, shows another small but unusually shaped rock structure. As Curiosity rolls around and up Mount Sharp, different layers of the landscape will be imaged and studied to better understand the ancient history of the region and to investigate whether Mars could once have harbored life.
Image credit: NASA, JPL-Caltech, MSSS
New Fossils Reveal Dino’s Aquatic Adaptations
Spinosaurus aegyptiacus — a meat-eating dinosaur bigger than Tyrannosaurus rex — was a fantastic swimmer, a new fossil study reports. This is a first for dinosaurs, long thought to be terrestrial beasts. Ever since the first fossils of S. aegyptiacus were examined over a century ago, much of our understanding of its morphology and ecology was left to speculation because the first fossils were destroyed during World War II. Now, a much more complete set of fossils suggests that the carnivore was semi-aquatic. Nizar Ibrahim and colleagues describe these new fossils, which include portions of a skull, axial column, pelvic girdle and limbs, from the Kem Kem beds of eastern Morocco.
[Artwork by Davide Bonadonna, Ibrahim et al., Science/AAAS. Click here for further information.]
An emu in the sky over ParanalSitting atop Cerro Paranal high above the Atacama Desert in Chile, two of the Very Large Telescope’s Unit Telescopes quietly bask in the starlight, observing the Milky Way as it arches over ESO’s Paranal Observatory.
Several interesting objects can be seen in this picture. Some of the most prominent are the two Magellanic Clouds — one Small (SMC), one Large (LMC) — which appear brightly in between the two telescopes. By contrast, the dark Coalsack Nebula can be seen as an obscuring smudge across the Milky Way, resembling a giant cosmic thumbprint above the telescope on the left.
The Magellanic Clouds are both located within the Local Group of galaxies that includes our galaxy, the Milky Way. The LMC lies at a distance of 163 000 light-years from our galaxy, and the SMC at 200 000 light-years. The Coalsack Nebula, on the other hand, is a mere stone’s throw away in comparison. At roughly 600 light-years from the Solar System, it is the most visible dark nebula in our skies.
The Coalsack has been recorded by many ancient cultures, and is identified as the head of the Emu in the Sky by several indigenous Australian groups. Aboriginal Australians are most likely the oldest practitioners of astronomy in the world, and they identify their constellations by use of dark nebulae — as opposed to stars, as is the Western tradition.
In the Southern hemisphere, these dark clouds are more prominent than in the Northern sky. Other cultures also had dark constellations — for example, the Inca in South America. A particularly important constellation to the Inca astronomers was one known as Urcuchillay (The Llama), representing the significance of the animals in their culture as a source of food, wool, and transport.
Image credit: ESO/Y. Beletsky
Snapshot of a shedding star
In this new Hubble image, the strikingly luminous star AG Carinae — otherwise known as HD 94910 — takes centre stage. Found within the constellation of Carina in the southern sky, AG Carinae lies 20 000 light-years away, nestled in the Milky Way.
AG Carinae is classified as a Luminous Blue Variable. These rare objects are massive evolved stars that will one day become Wolf-Rayet Stars — a class of stars that are tens of thousands to several million times as luminous as the Sun. They have evolved from main sequence stars that were twenty times the mass of the Sun.
Stars like AG Carinae lose their mass at a phenomenal rate. This loss of mass is due to powerful stellar winds with speeds of up to 7 million km/hour. These powerful winds are also responsible for the shroud of material visible in this image. The winds exert enormous pressure on the clouds of interstellar material expelled by the star and force them into this shape.
Despite HD 94910’s intense luminosity, it is not visible with the naked eye as much of its output is in the ultraviolet.
Image credit: ESA/Hubble & NASA