Mysteries of a Dark Universe

Cosmology, the study of the universe as a whole, has been turned on its head by a stunning discovery that the universe is flying apart in all directions at an ever-increasing rate.

Is the universe bursting at the seams? Or is nature somehow fooling us?

The astronomers whose data revealed this accelerating universe have been awarded the Nobel Prize for Physics.

And yet, since 1998, when the discovery was first announced, scientists have struggled to come to grips with a mysterious presence that now appears to control the future of the cosmos: dark energy.

On remote mountaintops around the world, major astronomical centers hum along, with state of the art digital sensors, computers, air conditioning, infrastructure, and motors to turn the giant telescopes.

Deep in Chile’s Atacama desert, the Paranal Observatory is an astronomical Mecca.

This facility draws two megawatts of power, enough for around two thousand homes.

What astronomers get for all this is photons, tiny mass-less particles of light. They stream in from across time and space by the trillions from nearby sources, down to one or two per second from objects at the edge of the visible universe.

In this age of precision astronomy, observers have been studying the properties of Continue reading Mysteries of a Dark Universe

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Hubble Burning Questions

From HubbleCast and the incomparable Dr. J. The episode features answers to questions submitted by the public. What is the most empty spot of space you have ever seen? What’s the longest single-shot exposure ever recorded of any object or area of space by Hubble? What are the farthest objects discovered by Hubble?

Three questions, just one answer. In 2003, Hubble was pointed at a part of sky which is, by normal standards at least, pretty empty. In particular, there are no bright stars in this area.

Now Hubble observed this field, which is only about a tenth the size of the full moon, for almost a million seconds. That’s around 11.3 days’ worth of total exposure time. The result is an image we call the Hubble Ultra Deep Field, and it is in fact the deepest optical image of the Universe that humanity has ever produced.

This is galaxy UDFj-39546284. Boring name, I know, but the point is that this is probably the most distant object ever discovered. Now its distance isn’t 100% confirmed yet, but it’s believed to be so far away that the light took 13.2 billion years to reach us. That’s about Continue reading Hubble Burning Questions

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Closest Known Approach by a Large Asteroid

2005 YU-55 is going to make a very close approach to the Earth on the night of November 8, 2011. At that time, its distance from Earth will be just under nine-tenths of the moon’s distance away from us. 2005 YU-55 cannot hit Earth at least over the interval that we can compute the motion reliably which extends for several hundred years.

It’s going to be moving very rapidly as it traverses the sky near the Earth on November 7, 8, 9 and 10th. In affect it’ll be moving straight at us from one direction and then it will go whizzing by and straight away from us in the other direction. So its motion across the sky will be close to degrees over the course of less than two days. It made a close approach to Earth about eighteen months ago in April of 2010. Colleagues of ours at Arecibo Observatory where able to observe this asteroid using the radar facility at Arecibo and they were able to obtain radar images that showed that this object is about 400 meters across. On November 8, 9, 10 we’ll be observing it again.

This time with both the Arecibo telescope and with the Continue reading Closest Known Approach by a Large Asteroid

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Pulsar Enigma Discovered

From NASA Astrophysics. Hidden deep within a group of ancient stars, there lurks a young and powerful enigma. This is NGC 6624, a globular cluster near our galaxy’s center thought to be about 10 billion years old. NASA’s Fermi Gamma-ray Space Telescope detects high-energy radiation from many globular clusters.

Usually what Fermi is seeing is the cumulative gamma rays from all of the old pulsars in these clusters. A pulsar is a rapidly spinning neutron star, which is the small, incredibly dense remnant of a much more massive star.

A teaspoon of matter from a neutron star weighs as much Mount Everest, and a neutron star is so compact that a ball about 15 miles across contains more matter than our sun. Neutron stars spin between 7 and 40,000 times a minute and form with incredibly strong magnetic fields. Rapid spin and intense magnetic fields drive powerful beams of electromagnetic radiation, including gamma rays. As the pulsar rotates, these beams sweep the sky like a lighthouse.

To a distant observer, the pulsar appears to blink on and off. Pulsars slow down as they age but some of the oldest pulsars spin hundreds of times a second. Each of these millisecond Continue reading Pulsar Enigma Discovered

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Dwarf Planet Crossing at the Solar System’s Edge

From ESOCast. Astronomers have accurately measured the size of the remote dwarf planet Eris for the first time. They caught it as it passed in front of a faint star. Eris also seems to be extremely reflective, probably because it is covered in a thin layer of frozen atmosphere.

Occultations are rather like eclipses —the background star disappears behind the object and reappears on its other side. As viewed from Earth, the brightness of the background star suddenly drops and then returns equally suddenly to its previous level. By looking at these two events, astronomers can measure the size and shape of the occulting foreground object. If they also know the mass of this object they can then determine its density.

The occultation technique has now enabled astronomers to learn a lot more about the dwarf planet Eris. Eris was identified as a large object in the outer Solar System in 2005. Its discovery was one of the factors that led to the creation of a new class of objects called dwarf planets and the reclassification of Pluto from planet to dwarf planet in 2006.

Eris is three times farther from the Sun than Pluto at the moment, and until now Continue reading Dwarf Planet Crossing at the Solar System’s Edge

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Tour of the Moon

A beautiful 1080p tour of our moon. It’s so clear and beautiful you’ll want to go there yourself. This virtual tour is based on data from NASA’s Lunar Reconnaissance Orbiter. Enjoy this “new” Moon and its noteworthy destinations.

Ancient peoples looked at the moon and saw in its patterns of shadow and light the figures of deities or animals.

The Italian scientist, Galileo Galilei, trained his telescope on our celestial companion and saw mountains and valleys much like those on Earth.

Scientists today, operating a fleet of spacecraft, are seeing evidence of past events that shaped the lunar landscape, and traces of water and minerals that may one day support a human presence.

Here’s the Mare Orientale, an impact crater nearly 4 billion years old. The color, coded for elevation, highlights a bulls-eye pattern of concentric rings.

Now, let’s go down under to the South Pole.

The pole sits within the wide rim of the famed Shackleton Crater. Direct sunlight never reaches the crater floor.

The Lunar Prospector spacecraft detected higher than normal amounts of hydrogen within the crater, which may indicate the presence of water ice.

From here, we travel to the far side of the moon. The South Pole-Aitken Basin is one Continue reading Tour of the Moon

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Ghost Lights from Earth Orbit

A “Ghost Light” is an unexplained luminescent phenomena. That’s how aliens might see Earth if they arrived with no awareness of its civilizations, atmosphere and climate, and magnetic field. Astronauts aboard the International Space Station are all too familiar with the city lights, the thunderstorms, and the aurorae that turn Earth into a planet of soft glows and flickering beams. This video has been made up of timelapse sequences captured aboard the ISS. Enjoy in 1080p!

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Re-Launching the First Science Rocket to Space

From NASA/JPL. A NASA scientist, physics professor, and model rocket hobbyist recreates an historic rocket launched by aeronautics pioneer Frank Malina. The first WAC Corporal dummy round was launched on September 16, 1945 from White Sands Missile Range near Las Cruces, New Mexico. After a White Sands V-2 rocket had reached 69 miles on May 10, a White Sands WAC Corporal reached 80 km (49 mi) on May 22, 1946 — the first U.S.-designed rocket to reach the edge of space (under the U.S. definition of space at the time). On February 24, 1949, a Bumper (a German V-2 rocket acting as first stage) bearing a WAC Corporal at White Sands accelerated to 5,150 mph to become the first flight of more than five times the speed of sound.

Scientists were later surprised when almost a year after the launch, tail fragments of the WAC Corporal rocket that reached 5,150 mph and an altitude of over 250 miles, were found and identified in the New Mexico desert near the launch site.

A few WAC Corporals survive in museums, including one at the National Air and Space Museum and another in the White Sands Missile Range Museum. Here are its specs:

Diameter: 1 ft Continue reading Re-Launching the First Science Rocket to Space

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The Great Solar Mag Flip

From NASA Heliophysics. The number of sunspots increases and decreases over time in a regular, approximately 11-year cycle, called the sunspot cycle. The exact length of the cycle can vary. It has been as short as eight years and as long as fourteen, but the number of sunspots always increases over time, and then returns to low again.

More sunspots mean increased solar activity, when great blooms of radiation known as solar flares or bursts of solar material known as coronal mass ejections (CMEs) shoot off the sun’s surface. The highest number of sun spots in any given cycle is designated “solar maximum,” while the lowest number is designated “solar minimum.” Each cycle, varies dramatically in intensity, with some solar maxima being so low as to be almost indistinguishable from the preceding minimum.

Sunspots are a magnetic phenomenon and the entire sun is magnetized with a north and a south magnetic pole just like a bar magnet. The comparison to a simple bar magnet ends there, however, as the sun’s interior is constantly on the move.

By tracking sound waves that course through the center of the sun, an area of research known as helioseismology, scientists can gain an understanding of what’s deep Continue reading The Great Solar Mag Flip

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Einstein’s Greatest Blunder

Excerpt from “Mysteries of a Dark Universe.” Albert Einstein sought to explain why the gravity of all the stars and gas out there didnt simply cause the universe to collapse into a heap. Following the discovery of the expanding universe, he admitted to the “greatest blunder” of his career.

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