Stonehenge

Apart from the mechanical devices made of metal, wood or ivory, some early astronomers relied on massive masonry structures for astronomical observations. Among the oldest such structures is the megalithic ruin known as Stonehenge in England. Stonehenge was constructed of 56 individual segments and was possibly used as a method of determining several astronomical events.

 Investigators over the last 100 years have revealed that Stonehenge was build in several stages from 2800-1800 BC. It seems to have been designed to allow for observation of astronomical phenomena - summer and winter solstices, eclipse and more. The stone pillars may have been constructed so that the alignment of the sun, with respect to the pillars, would allow astronomers to determine the beginnings and mid points of the seasons. Stonehenge may have been used as a tool to determine the position of the moon throughout the year, roughly predicting the occurrence of eclipses.

Asteroid Zips By Orion Nebula

This image shows the potentially hazardous near-Earth object 1998 KN3 as it zips past a cloud of dense gas and dust near the Orion nebula. NEOWISE, the asteroid-hunting portion of the Wide-field Infrared Survey Explorer, or WISE, mission, snapped infrared pictures of the asteroid, seen as the yellow-green dot at upper left. Because asteroids are warmed by the sun to roughly room temperature, they glow brightly at the infrared wavelengths used by WISE.

Astronomers use infrared light from asteroids to measure their sizes, and when combined with visible-light observations, they can also measure the reflectivity of their surfaces. The WISE infrared data reveal that this asteroid is about .7 mile (1.1 kilometers) in diameter and reflects only about 7 percent of the visible light that falls on its surface, which means it is relatively dark.

View From Mars Orbiter Showing Curiosity Rover at 'Shaler'

NASA's Mars Science Laboratory rover Curiosity appears as a bluish dot near the lower right corner of this enhanced-color view from the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter. The rover's tracks are visible extending from the landing site, "Bradbury Landing," in the left half of the scene. Two bright, relatively blue spots surrounded by darker patches are where the Mars Science Laboratory spacecraft's landing jets cleared away reddish surface dust at the landing site. North is toward the top. For scale, the two parallel lines of the wheel tracks are about 10 feet (3 meters) apart.

NASA's Spitzer Telescope Celebrates 10 Years in Space

Ten years after a Delta II rocket launched NASA's Spitzer Space Telescope, lighting up the night sky over Cape Canaveral, Fla., the fourth of the agency's four Great Observatories continues to illuminate the dark side of the cosmos with its infrared eyes.

What is Hubble Constant?

Q 236: Question of the Day - 16 April 2013 (Week 16)

What is Hubble Constant?

Answer To Question 235

A235: The horizon is an imaginary circle that delimits the sky and the Earth, or an extension of the plane of the observer (at an altitude of 0 degrees).

Hints of Dark Matter Possibly Seen

These illustrations, taken from computer simulations, show a swarm of dark matter clumps around our Milky Way galaxy. Image released July 10, 2012.

CREDIT: J. Tumlinson (STScI)

Crater's Central Pit | Space Wallpaper

This cool space wallpaper shows a perspective view of a 50 km diameter crater in Thaumasia Planum. The image was made by combining data from the High-Resolution Stereo Camera on ESA’s Mars Express with digital terrain models. The image was taken on Jan. 4, 2013 during orbit 11467, and shows a close up view of the central ‘pit’ of this crater, which likely formed by a subsurface explosion as the heat from the impact event rapidly vapourised water or ice lying below the surface.

Credit: ESA/DLR/FU Berlin (G. Neukum)

Detecting and Tracking of asteroids

An infrared sensor that could improve NASA's future detecting and tracking of asteroids and comets has passed a critical design test.

Jonckheere 900

The object in this image is Jonckheere 900 or J 900, a planetary nebula — glowing shells of ionized gas pushed out by a dying star. Discovered in the early 1900s by astronomer Robert Jonckheere, the dusty nebula is small but fairly bright, with a relatively evenly spread central region surrounded by soft wispy edges.

Hubble Catches Dusty Detail in Elliptical Galaxy NGC 2768

The soft glow in this image is NGC 2768, an elliptical galaxy located in the northern constellation of Ursa Major (The Great Bear). NGC 2768 appears here as a bright oval on the sky, surrounded by a wide, fuzzy cloud of material.

What is horizon?

Q 235: Question of the Day - 15 April 2013 (Week 16)

What is horizon?

Auroramax

Canada's automated aurora camera tweeted this photo on March 17, 2013

Answer To Question 234

A234: The heliopause is the boundary of the heliosphere of the Sun in which the solar wind's density decreases greatly (and its speed also declines). The location of this transition region is unknown, but must be at more than 50 AU from the Sun.

Russian Cargo Craft Departs

An unpiloted Russian Progress cargo ship departed the International Space Station early Monday, clearing the way for the arrival of the next Russian space freighter. 

What is Heliopause?

Q 234: Question of the Day - 12 April 2013 (Week 15)

What is Heliopause?

Answer To Question 233

A233: The HD (Henry Draper) number is an identifying number assigned to the strs in the Henry Draper catalog. In this system, every star is classified by its stellar spectrum. This sytem is named for the astronomer Henry Draper, but was cataloged by Annie J. Cannon (225,300 stars), and later extended by Margaret W. Mayall. For example, the star Vega is HD 172167 (the spectral type is not in the HD number).

Sunspot Beauty

JP Brahic took this photo from France on April 5, 2013. He used a refractor Astro-Physics 155mm F/D 8.5 and a Bassler ACA1300 camera with filter H-Alpha 1A ° to capture the image.CREDIT: JP Brahic

Spring Fling: Sun Emits a Mid-Level Flare

NASA's Solar Dynamics Observatory captured this image of an M6.5 class flare at 3:16 EDT on April 11, 2013. This image shows a combination of light in wavelengths of 131 and 171 Angstroms. Credit: NASA/SDO.

Ice Cloud Heralds Fall at Titan's South Pole

The change of seasons on Titan is creating new cloud patterns at Titan's south pole. Here, a combination of red, green and blue images taken by the wide-angle camera on NASA's Cassini spacecraft shows a vortex over the south pole in natural color. A more recent ice cloud, detectable only at infrared wavelengths, also has formed over this pole. Credit: NASA/JPL-Caltech/Space Science Institute/GSFC