Category Archives: Sky and Outer Space

Star goes Boom !

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On July 4, 1054, a supernova (SN 1054) was observed by astronomers and stargazers across theNorthern Hemisphere, and possibly Australia. Its remnant, the Crab Nebula, is among the most-studied objects outside our solar system.
A supernova is one of the most explosive events in the universe. A supernova occurs when amassive star runs out of nuclear fuel (mostly hydrogen and helium). The core of the starcollapses, violently ejecting its outer envelope of material into space in a huge shock wave. These blast materials are the filaments still visible as the Crab Nebula.
The star that went supernova in 1054 was so massive that it left only a rapidly rotating ball ofneutrons called a pulsar. The Crab Pulsar is only about 20 kilometers (12 miles) in diameter, but has a mass greater than the Sun! The Crab Pulsar pulses, or spins, about 30 times a second.
SN 1054 was visible as a bright, glowing star for about two years! Astronomers in China, Japan, and what is today Iraq recorded the event. Some historians think that petroglyphs left byAncestral Puebloans may also have recorded SN 1054. Other historians think the oral tradition ofAboriginal Australians may also refer to SN 1054.

Astronauts Spot Hurricane Arthur From Space Station (Photos, Video)

A stunning photo snapped by astronauts aboard the International Space Station shows Hurricane Arthur churning off the coast of Florida, heading north.

The image, taken on Wednesday morning (July 2) by a crewmember of the orbiting lab’s current Expedition 40, actually captures Arthur when it was still classified as a tropical storm. (Arthur strengthened to hurricane status early Thursday.)

“Surrounded by bright green waters, the Bahamas Islands are south of the storm in the lower right corner of the photo,” NASA officials wrote in adescription of the picture. “The U.S. coastline stretches along the left side of the photo.”

 

 

Robotic eyes are keeping tabs on Arthur from orbit as well. NASA’s Aqua satellite took a picture on Wednesday afternoon as it passed over the storm, for example, revealing that Arthur’s eye was still covered by clouds at the time.

NASA's Aqua Satellite Captures Tropical Storm Arthur
This image of Tropical Storm Arthur off the coast of Florida was taken by the MODIS instrument aboard NASA’s Aqua satellite on July 2, 2014.
Credit: NASA Goddard MODIS Rapid Response Team

Aqua has also been gathering data on Arthur in infrared light. One infrared image captured Thursday (July 3) shows thunderstorms around the storm’s center with temperatures around minus 63 degrees Fahrenheit (minus 53 degrees Celsius), NASA officials said.

Arthur is the first tropical storm of the 2014 Atlantic hurricane season. It took shape off southern Florida on Tuesday (July 1) and is currently heading north off the East Coast.

 

 

As of Thursday afternoon, Arthur was about 70 miles (113 kilometers) south-southwest of Cape Fear, North Carolina and featured maximum sustained winds of 90 mph (150 km/h). The National Hurricane Center (NHC), which is run by the U.S. National Weather Service, has issued a hurricane warning for areas from Surf City, North Carolina north to the Virginia border.

Arthur will likely come close to North Carolina’s Outer Banks later Thursday and early Friday (July 4) but should then turn to the northeast, forecasters say.

The storm is expected to be a Category 2 hurricane when it passes over or near the North Carolina coast, NHC officials said in an advisory Thursday. (Meteorologists classify hurricanes based on wind speed from Category 1, the weakest, to Category 5, the most powerful.) But Arthur should begin weakening Friday night and will likely be downgraded to a “post-tropical cyclone” on Saturday (July 5), they added.

Why the Same Side of the Moon Always Faces the Earth

One Moon “day” is approximately 29 1/2 Earth days. This rotation coincides with its orbit around the Earth so that we only see about 59% of the surface of the Moon from Earth. When the Moon first formed, its rotational speed and orbit were very different than they are now. Over time, the Earth’s gravitational field gradually slowed the Moon’s rotation until the orbital period and the rotational speed stabilized, making one side of the Moon always face the Earth.

How does this work? Simply put -tidal friction. For a slightly less simple explanation, we’ll have to put our science caps on. But stick with it; it’s fascinating. I promise.

To start, think of how the Moon causes major tides on the Earth due to the Moon pulling at the Earth via its gravitational field. The Earth has this same effect on the Moon and, being 81.28 times more massive, the effect is much more powerful.

So, as the mass of the Moon is attempting to go one way (in a straight line), the Earth is simultaneously pulling it another way (towards the Earth). Further, the effect of the Earth’s gravitational field is stronger on the side of the Moon closest to the Earth than on the far side (and the same with the Moon’s gravitational field’s effect on the different parts of the surface of the Earth).

This combination essentially stretches the Earth and Moon, creating tidal bulges on both celestial bodies. This occurs on both sides of each, with the bulge on the sides closest together from gravity and on the sides farthest away from inertia. In the latter case, the matter is less affected by the gravitational force with inertia dominating in this instance. To put it another way, the matter is trying to move in a straight line away from the Earth and the gravitational forces here aren’t as strongly able to overcome this, which creates the bulge on that side.

So back before the Moon was tidally locked with the Earth, the bulge on the side of the Moon nearest to Earth ended up slightly leading thanks to friction and the fact that the Moon rotated faster than its orbital period around the Earth. So with this slightly leading bulge being offset from the line of gravitational pull between the Moon and Earth, this created a torque, which overtime resulted in the Moon’s rotation slowing until it became tidally locked with the Earth; thus, only one side faces the Earth. (Note: the bulge on the far side of the Moon had the opposite effect, but the bulge closest to the Earth dominated the interaction.)

You’ll note, though, that I said we actually get to see about 59% of the surface of the Moon from Earth, not 50%. The discrepancy comes from the fact that the Moon’s orbit around the Earth isn’t perfectly circular, more of an ellipse. As the Moon’s distance from the Earth increases and decreases, its angular speed changes, while its rotational speed stays the same. The result is that we get to see an extra 9% of its surface than we would if it had a perfectly circular orbit.

The other side of this, as you may have guessed, is that the Moon has the same effect on the Earth and is gradually slowing the Earth’s rotation in the exact same way the Moon became tidally locked with the Earth. Further, as the Moon slows the Earth’s rotation, a small portion of the Earth’s rotational momentum gets transferred to the Moon’s orbital momentum, with the result being that the average radius of the Moon’s orbit increases at about 3.8 centimeters per year with the current continental positions and barring major geological events. (Contrary to what you’ll often read, the Moon isn’t getting all the energy here, most of it is being converted to heat via friction, with only an estimated 3% of the energy in the interaction being “stolen” by the Moon.)

Thus, the distance between the Moon and the Earth changes gradually and is more or less in step with the rotational period change. It should be noted, though, that it’s not a constant change as things like major earthquakes, glacial changes, continental drift, and other such geological events play a role here, which is why leap seconds aren’t added at regular intervals, but only when needed. But the overall effect is that over time, the Moon is getting farther and farther away from the Earth every year, while the Earth’s rotation is slowing down.

In theory, at some point tens of billions of years from now (with the exact timeframe being extremely difficult to nail down due to so many unknowable factors) the same side of the Earth will always face the Moon, with the Earth only rotating once per lunar cycle, which at that point most estimates indicate should be about 47 current Earth days long.

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“In theory”… but this will likely never happen. Why? In about 1 to 2 billion years or so, the Sun’s brightness will have increased sufficiently to vaporize all water on the surface of the Earth, getting rid of the ocean tides altogether, which is a huge factor in this interaction. However, there still would be some bulging of the Earth’s crust to continue the process to a much lesser extent.

In 5 to 6 billion years, the Sun will be around the peak of its Red Giant phase, and according to the latest models, even with the Sun losing quite a bit of mass during this process, thus making the Earth’s orbit farther out, the Sun should just barely consume the Earth and Moon many billions of years before such a dual tidal lock can occur.

Bottom line, at some point in the next billion years or so, humans will need to either find another home, or figure out how to manually move our current one to a farther out orbit, keeping Earth in the habitable zone of our solar system.

  What Happened To The Flags On The Moon?

 

On July 10, 1969, Apollo 11 touched down on the moon. At 10:56 pm eastern standard time, Neil Armstrong accomplished another first. With the immortal words, “That’s one small step for a man, one giant leap for mankind,” (or something like that) Neil Armstrong became the first human to step foot on a major celestial object. Soon after, Buzz Aldrin joined Armstrong on the alien surface. The two of them spent the next two and half hours exploring, taking pictures, and collecting samples.

Before they took off back to Earth, Apollo 11 left evidence of their rendezvous with the moon. Besides Armstrong’s boot print and a bunch of junk, the astronauts also planted a three foot by five foot nylon American flag mounted on a pole into the ground. Subsequent Apollo missions that made it to the moon followed suit. But what happened to all of these flags? Are they still standing? Do they even still exist after nearly a half century on the moon?

As for the Apollo 11 flag, when the engine came on and the spaceship shot up away from the moon, Aldrin said he saw the flag get knocked over by the rocket blast. Beyond that, it was thought that there would be little chance the flag would survive on the harsh environment of the moon. From the extremely abrasive lunar dust to the sun’s unfiltered ultraviolet rays, the flag most likely would quickly be bleached white and disintegrate.

In fact, the flag was never intended to last long. It was purchased from the New Jersey-based flag company Annin for five dollars and fifty cents (which is about thirty five dollars today). (Annin has been making flags since 1847, making them the oldest flag manufacturer in the US today.) The flag was made with basic, ordinary nylon with no intention of existing on the moon for very long, much less for decades or more. In 2008, Dennis Lacarrubba, an employee of Annin, told Smithsonian that he couldn’t “believe there would be anything left. I gotta be honest with you. It’s gonna be ashes.”

Five other, less talked about, flags got planted on the moon during Apollo 12, 14, 15, 16, and 17. Apollo 13 never made it to the moon because, well… they had some problems as you’re no doubt familiar. These flags were also not specially made to survive on the moon, but just ones anyone could pick up at a local store.

Apollo 17, launched on December 7, 1972, featured the last humans to walk on the moon. As astronaut Eugene Cernan and geologist Harrison “Jack” Schmitt were placing the American flag into the lunar surface, Cernan apparently quipped that if he pounded the flag extra hard into the moon, that it may just last a million years.

While no human has walked on the moon since 1972, plenty of crafts sent by various nations have orbited it, taking pictures as they went. As the technology advanced and the pictures became sharper, portions of the moon’s surface were seen in great detail for the first time since 1972.

This brings us to 2012. The Lunar Reconnaissance Orbiter Camera, or LROC for short, was first launched in June 2009. It spent over three years orbiting the moon and taking pictures with its high-resolution camera. In 2012, images sent back by LROC confirmed that all but Apollo 11’s flag and possibly Apollo 15’s flag not only survived, but are still standing.

By looking at the photos from different points in the day, the movement of shadows confirm that the flags, in some form or another, are still there. Apollo 15’s flag is still generally thought to be standing, as there is footage of this after the astronauts left. But the LROC images showed no distinctive shadow for it, as with the others confirmed still standing. That said, given the other flags seemed to have survived and it was still standing after the astronauts left, there is little reason to think this particular one disintegrated when the others did not. For that matter, it’s possible the Apollo 11 flag is still intact as well, simply lying on the lunar surface.

So what about the condition of the flags? The general consensus is that the colors have probably faded to white.

The LROC was also able to document other things left behind by the various Apollo missions, including tracks made by astronauts, backpacks, and rovers that were left. As technology progresses, we will soon be able to see the flags for ourselves to confirm the exact state, instead of relying on shadow movement.

NASA Space Rover Drives On The Underside Of The Ice

NASA just completed a test of an early prototype-maybe just an early, early precursor-space rover that may be flown to explore the Jupiter moon Europa. What’s cool is that the rover is designed to float on the underside of the ice and “rove as if the underside of the ice is the ground.” Up is down, down is up.

NASA says that it’s the first time ever that an underwater, under-ice, untethered vehicle has been operated through satellite link. It’s one of the cool technologies that can help us better understand the world we live in now while preparing us for exploration of future worlds.

 

 

The Earth Looks Flat In This Photo Taken From Space

Believe it or not, some idiots think that Earth doesn’t rotate and others still think that Earth is flat.I’m sure the latter group would love this picture just taken by our space Captain America-astronaut Reid Wiseman. The angles on those two coasts converging make Earth’s spheroidal surface look strangely flat.

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The image shows the south tip of Morocco and the north top Western Sahara, an old Spanish colony now occupied by the Kingdom of Morocco.

Night in the City: Milky Way Dazzles Over New Zealand Lights (Photo)

The Milky Way shines over the bright city lights of Wellington, New Zealand in this stunning image from a veteran night sky photographer.

Astrophotographer Mark Gee captured this view of the Milky Way over Evans Bay near Wellington in early June. Unlike some stargazers, who sometimes travel great distances to capture memorable space images, Gee simply stepped outside. “I didn’t have to go far to photograph this one, as I shot it from my balcony,” he said.

Wellington has the second-largest population of the country, and the city serves as the capital of the country. Wellington lies at the southwestern tip of New Zealand’s North Island. Gee told Space.com that his image represents a single exposure, which he found surprising giving the amount of detail and the Milky Way stretching across the night sky.

 

milky-way-over-evans-bay

 

Gee said the shot required care to get right, adding that he had to walk a fine line between overexposing the city below and underexposing the dark night sky. Gee used a Canon 6D camera with a Canon 14mm f/2.8 lens, with settings of a 10-second shutter, aperture of f/2.8 and a ISO of 3200 to capture the image.