Blog

The Most Dangerous Spacewalk In History

Friday, August 22nd 2014 03:14 AM

As seen by Rosetta: comet surface variations

Friday, August 22nd 2014 02:44 AM

A new image of Comet 67P/Churyumov-Gerasimenko shows the diversity of surface structures on the comet's nucleus. It was taken by the Rosetta spacecraft's OSIRIS narrow-angle camera on August 7, 2014. At the time, the spacecraft was 65 miles (104km) away from the 2.5-mile-wide (4km) nucleus.In the image, the comet’s head — in the top half of the image — exhibits parallel linear features that resemble cliffs, and its neck displays scattered boulders on a relatively smooth, slumping surface. In comparison, the comet's body — lower half of the image — seems to exhibit a multivariable terrain with peaks and valleys and both smooth and rough topographic features.Launched in March 2004, Rosetta was reactivated in January 2014 after a record 957 days in hibernation. Composed of an orbiter and lander, Rosetta's objectives are to study Comet 67P/Churyumov-Gerasimenko up close in unprecedented detail, prepare for landing a probe on the comet's nuc...

Read More

Curiosity Rover on Mars Stalled by 'Hidden Valley' Sand Trap

Friday, August 22nd 2014 02:29 AM

NASA's Mars rover Curiosity may have to choose a new route to the base of a huge Red Planet mountain.    The 1-ton Curiosity rover had been heading for Mount Sharp — a 3.4-mile-high (5.5 kilometers) mountain in the center of Mars' Gale Crater — via "Hidden Valley," a sandy swale that's about the length of a football field. But Curiosity turned back shortly after entering the valley's northeastern end earlier this month, finding the sand surprisingly slippery, NASA officials said.  "We need to gain a better understanding of the interaction between the wheels and Martian sand ripples, and Hidden Valley is not a good location for experimenting," Curiosity project manager Jim Erickson, of NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California, said in a statement. [Mars Rover Curiosity's Latest Amazing Photos]  There is no way out of Hidden Valley save exits at its northeastern and southw...

Read More

Flower Power Starshade Unfurls in Space

Monday, July 21st 2014 11:55 PM

Embedded video from NASA Jet Propulsion Laboratory California Institute of Technology

Read More

Astronomy of Aztec Civilization

Monday, July 14th 2014 11:38 PM

If you look at the astronomy of the Aztecs, you will find something quite unusual.  While for many other civilisations the night sky has been a source of stability and unchanging harmony, Aztecs were concerned about a lack of stability and the potential destruction of the world coming from the sky.  The Aztecs used a complex calendar system characteristic of Mesoamerican civilisations. It combined a count of 365 days based on the solar year with a separate calendar of 260 days based on various rituals. Every 52 years, both calendars would overlap and a new cycle would commence.  Unlike other civilisations, such as the Mayans, the Aztec seriously considered the possibility that the world could be destroyed and recreated at the end of such a 52-year cycle.  Such cosmological understanding has far-reaching cultural and social consequences. While the notion of the world’s destruction (and recreation) is found in other cosmologies as well – whether it is...

Read More

Primary Mirrors of the James Webb Space Telescope

Friday, July 11th 2014 03:21 AM

How the Atmosphere Affects Telescope Viewing

Thursday, July 10th 2014 06:22 AM

Introduction An observer, be they at a mountain top observatory, or in their own back yard must, at all times contend with the Earth’s atmosphere. It is a notoriously unpredictable and limiting factor in obtaining fine views of the Planets, and close binary stars. Many often comment, especially here in the UK that seeing is all too often mediocre on most nights, but what are the factors that contribute to this?. Are there ways and signs, which indicate whether the atmosphere, will be stable or turbulent on a given night?.What is “seeing”? So what exactly is atmospheric seeing? - it is high frequency temperature fluctuations of the atmosphere, and the mixing of air “parcels” of different temperatures/densities. This behaviour of the atmosphere is seen at the eyepiece as a blurred, moving, or scintillating image. There are roughly 3 main areas where Atmospheric turbulence occurs. Near ground seeing (0 – 100metres or so.) central troposphere (100m &nd...

Read More

Astronomers Create 3-D Model of Ancient Supernova

Thursday, July 10th 2014 05:51 AM

In the middle of the 19th century, the massive binary system Eta Carinae underwent an eruption that ejected at least 10 times the Sun's mass and made it the second-brightest star in the sky. Now, a team of astronomers has used extensive new observations to create the first high-resolution 3-D model of the expanding cloud produced by this outburst."Our model indicates that this vast shell of gas and dust has a more complex origin than is generally assumed," said Thomas Madura from NASA's Goddard Space Flight Center in Greenbelt, Maryland. "For the first time, we see evidence suggesting that intense interactions between the stars in the central binary played a significant role in sculpting the nebula we see today."Eta Carinae lies about 7,500 light-years away in the southern constellation Carina and is one of the most massive binary systems astronomers can study in detail. The smaller star is about 30 times the mass of the Sun and may be as much as a million times more luminous. The pr...

Read More

First Stop, Pluto; Journey of New Horizon

Thursday, July 10th 2014 12:23 AM

Scientists looking for targets beyond Pluto for NASA’s New Horizon’s spacecraft to visit will get more time on the Hubble Space Telescope, managers decided after a two-week pilot study revealed at least two candidate objects.  The New Horizons team had spent three fruitless years using ground-based telescopes to find aKuiper Belt Object that will be within range of New Horizons after its July 14, 2015, flyby of Pluto. Last month, scientists got two weeks of observing time on Hubble for initial scans.  The deal was that if they found at least two candidates, they could have another 160 orbits worth of telescope time to ferret out a second suitable target for New Horizons.  The spacecraft, which was launched in 2006, is on track to become the first probe to visit the dwarf planet Pluto, located some 4.7 billion miles from Earth in the Kuiper Belt. New Horizons must fire its maneuvering engine by December 2015 to put itself on track for an...

Read More

Tidal Forces, Plate Tectonics, and Human Survival

Wednesday, July 9th 2014 01:00 AM

For more than three billion years now, Earth's ability to support life has been a delicate balancing act. Climatic periods of severe cold or hot have brought life to its knees. Glaciers covered the planet in the "snowball Earth" epoch, which ended some 650 million years ago. During the extremeheat of the early Triassic period around 250 million years ago, tropical sea temperatures exceeded 100 degrees Fahrenheit.  But the temperature pendulum has always swung back from these extremes, thanks in large part to the moderating phenomenon of plate tectonics. The sliding movements of Earth's crust regulate the amount of heat-trapping carbon in our atmosphere by trapping the carbon in the seafloor and releasing it later by way of volcanoes. In this way, the "carbon cycle" has helped stir our planet out of frozen slumbers and has curbed the greenhouse effect.  Yet all good things, as the saying goes, must come to an end. The driver of Earth's tectonics is heat from our planet's slo...

Read More