Stories tagged Earth and Space Science

Aug
19
2006

Satellite vulnerability: Photo from Wikipedia Commons
Satellite vulnerability: Photo from Wikipedia Commons

One possible solution

The high energy particles spewed out of sunspots can knock out satellites and electric power grids. To prevent this from happening the US Air Force and the US Defence Advanced Research Projects Agency (DARPA) have proposed using very low frequency radio waves to flush particles from radiation "belts" above Earth and dump them into the upper atmosphere over either one or several days.

What are the consequences?

This deluge of dumped charged particles would temporarily change the ionosphere from a "mirror" that bounced high frequency radio waves around the planet to a "sponge" that soaked them up, says Dr Craig Rodger of Otago University's physics department.
“Airplane pilots and ships would lose radio contact and some Pacific Island nations could be isolated for as long as six to seven days, depending on the system’s design and how it was operated,” he says.
GPS would likely also suffer large-scale disruptions, as signals between ground users and satellites were scrambled by the ionosphere, he added. Otego media release

Is it worth it?

Can people like Joe can go without geocaching for a week. Smart bombs also would need to take a breather because they use GPS to find their targets. We are seeing a minimum of sunspot activity right now. Sunspots peak every eleven years. The last memorable blast from the sun was July 14, 2000 so we need to make up our minds before 2011.

Aug
17
2006

Aurora watch: Photo by Craig M. Groshek, via Wikipedia
Aurora watch: Photo by Craig M. Groshek, via Wikipedia

Here it comes

Sunspot 904 erupted yesterday, Aug.16. A lot of astronomers were watching as it happened. See pictures 1, 2, 3, 4, 5.

Aurora watch alert

A coronal mass ejection (CME, movie) is heading toward Earth and could spark a geomagnetic storm when it arrives on August 18th or 19th. The cloud was hurled into space yesterday by a C3-class explosion in the magnetic field of sunspot 904. Sky watchers, prepare for auroras.

Watch for Northern Lights Friday and Saturday night.
Source; SpaceWeather

Aug
14
2006

Space station: NASA graphic
Space station: NASA graphic

Space station construction to resume.

After a three and a half year hiatus, construction of the International Space Station (ISS) is finally going to continue. One of the largest pieces, a power generating structure, will be attatched to the ISS. Weighing 17.5 tons, the 240 foot solar arrays on the P3P4 truss segment will generate 20 kilowatts. The 11 day mission could begin as early as August 27. Atlantis' crew members have been training for this mission for four and a half years, since before the Columbia tragedy.WMV video link

The ISS is about half finished

The station is nearly halfway through assembly. The next four flights will bring new truss segments, massive structural support beams, to the complex. The new segments will increase the mass of the station by almost 40 tons, the maximum weight of an 18-wheeled semi-truck.
Two of the trusses include huge sets of solar array wings, totaling more than 17,000 square feet. With a wingspan area the size of a national standard hockey rink, the panels will carry 130,000 solar cells. The new segments include giant rotary joints to allow the tips of the station "backbone" to move as the massive panels track the sun. NASA

To construct the station, more than 100 international space flights will have been conducted on five different types of vehicles launched from four different countries. If all goes well the ISS will be completed in 2010.

Read more about the ISS at Wikipedia.

Aug
14
2006

Geocache: Typical geocache and contents.  Photo courtesy Skinny Mike, Flickr Creative Commons.
Geocache: Typical geocache and contents. Photo courtesy Skinny Mike, Flickr Creative Commons.

I thoroughly enjoy geocaching. Geocaching is basically a treasure hunt using the Global Positioning System (GPS) to locate the treasure (often simply trinkets – the “treasure” for me is the find) which can be hidden anywhere in the world. I’ve been a geocacher for over a year now, and have successfully found over 200 geocaches. I love the game because it gets me outside, gets me active, and brings me to places that I have never been before, such as city parks, wildlife refuges, scenic overlooks, and historical monuments. While I have enjoyed my geocaching experience, I have been pretty ignorant as to how the Global Positioning System that makes geocaching possible, works. Until now!

The Global Positioning System was developed by the U.S. Military as a navigation system for their use and became operational in 1993. In 1996 President Bill Clinton issued a policy directive declaring GPS to be a dual-use (civilian and military) system.


GPS satellite: GPS satellite. Image courtesy NASA.

The GPS system consists of 29 satellites (as of August 2006). 24 are all that is needed for global coverage, and three of the 29 are held back as spares in case of any malfunctions. Each satellite orbits the Earth twice each day at an altitude of around 12,000 miles. The orbits are set up so that at least four satellites are always within line of sight from any place on Earth.

The handheld GPS receivers that are used for geocaching (and other uses) locate four or more of these satellite signals, figure out the distance to each, and use this information to determine its own location. The receivers used to have a built in degree of error called selective availability that caused intentional errors in the publicly available navigation signals, making it difficult to use a privately owned receiver for malicious purposes. This feature was disabled in 2000, but can be reactivated should it be found to be needed. The best accuracy I have ever obtained was +/- 8 feet.

Besides for treasure hunting, the Global Positioning System has many other uses. Since it was developed by the military, they use it for a wide variety of purposes – including guiding missiles. GPS receivers are becoming more commonplace in cars as navigation tools.

Discovery landing: Space shuttle Discovery makes the first GPS assisted space shuttle landing on July 17, 2006.  Image courtesy NASA.
Discovery landing: Space shuttle Discovery makes the first GPS assisted space shuttle landing on July 17, 2006. Image courtesy NASA.

The system is used by an increasing number of airplanes to assist with landings, and the most recent landing of space shuttle Discovery was the first to use the GPS satellites to give navigational guidance for landing. GPS was previously a back-up capability to the microwave system currently used. We’re seeing GPS become a larger part of our lives as we look to utilize this incredible system.

I’d encourage anyone who has not gone geocaching to do so – it’s fun, and it gets you outside, and active. Good luck!

Aug
10
2006

Magnetosphere: Solar particles interact with magnetosphere. NASA graphic via wikipedia
Magnetosphere: Solar particles interact with magnetosphere. NASA graphic via wikipedia

SUNSPOT 904

A large and beautiful new sunspot is emerging from the sun's eastern limb: image. So far it poses no threat for Earth-directed solar flares, but this could change. The spot is growing fast and turning toward Earth. Stay tuned for updates.

11 year sun spot cyle

We are currently at the lowest activity of the 11 year sunspot cycle. Sun spots, when facing Earth can send solar flares toward Earth. The Earth's magnetosphere shields us from these high energy particles but astronauts in space need to be concerned.

James Van Allen dies at 91

I think it is fitting to mention that James Van Allen died yesterday Aug 9, 2006 He discovered of the Van Allen radiation belts, which I associate with the Nothern lights, which come from sun spot flares.

Aug
06
2006

Triangulum galaxy (M33)
Triangulum galaxy (M33)Courtesy NASA

Universe may be 15.8 billion years old

The Hubble constant, formulated by Edwin Hubble in 1929, has remained fairly constant since the 1950's. Kris Stanek, associate professor of astronomy at Ohio State, and his coauthors are publishing a paper that may change the accepted value of the Hubble constant and also the accepted size and age of the universe.

They studied two of the brightest stars in M33, which are part of a binary system, meaning that the stars orbit each other. As seen from Earth, one star eclipses the other every five days.

They measured the mass of the stars, which told them how bright those stars would appear if they were nearby. But the stars actually appear dimmer because they are far away. The difference between the intrinsic brightness and the apparent brightness told them how far away the stars were -- in a single calculation.

To their surprise, the distance was 15 percent farther than they expected: about 3 million light-years away, instead of 2.6 million light-years as determined by the Hubble constant.

Astronomers crunch numbers, universe gets bigger

This new method took 10 years to develop. To make such a drastic change to the accepted view of the universe will require additional experimentation.

"Our margin of error is now 6 percent, which is actually pretty good," Stanek said. Next, they may do the same calculation for another star system in M33, to reduce their error further, or they may look at the nearby Andromeda galaxy. The kind of binary systems they are looking for are relatively rare, he said, and getting all the necessary measurements to repeat the calculation would probably take at least another two years.

Soure article: Ohio State University Research Archive

Jul
15
2006

Watch that wave:: This historical photo gives a little feel for what a freak wave might be able to do to a ship. An actual freak wave would be taller, ranging in height from 90 to 140 feet high.
Watch that wave:: This historical photo gives a little feel for what a freak wave might be able to do to a ship. An actual freak wave would be taller, ranging in height from 90 to 140 feet high.
The term “Freak of Nature” gets inappropriately thrown around a lot these days. But meteorologists and oceanographers are using the term very appropriately as they learn more about huge ocean waves.

Once thought to be just the old sea tales from the alcohol-induced memories of sailors, more and more credible scientific evidence is being pinpointed about “freak waves,” huge walls of water that sweep across the ocean under just the right oceanic conditions.

I stumbled into learning about freak waves the other night while watching a PBS show called “When Nature Strikes Back: Freak Waves.” The hour-long program documented some pretty interesting things about freak waves. So if you’ve read “A Perfect Storm” or seen the movie of the same name, you probably know something about this already.

To qualify as a freak wave, the wall of water needs to be at least 90 feet (about 30 meters) high. The largest documented freak wave actually measured in at 140 feet high. Back in the days of wind-powered ocean travel, seafarers called freak waves “holes in the ocean” due to the large depression in the water level in advance of the freak wave.

So what’s going on to make a freak wave? It could be the result of a couple factors.

First, it might be the result of high winds pushing along the tops of already high ocean swells. If the wind direction and speed match up to a wave just right, it can push the wave faster so it catches up with another wave ahead of it. Those waves combine their size and if this happens a few times, you suddenly have a very large wave.

Second, two or more wave or storm systems can merge and basically create the same effect. Waves piggybacking on top of each other will add to their size and can lead to a huge wall of water.

Years ago without the aid of modern electronic communication technology, ships that were wiped out by freak waves were simply lost. There was no record of what had happened. Likewise, with better weather tracking technology today, ships can usually avoid the dangerous conditions of freak waves. But researchers are still finding out their impacts.

An offshore oil rig in the North Atlantic was toppled by a freak wave several years ago. And the television show also recreated the tragic tale of an amateur wave photographer who was swept away to sea off the coast of Ireland trying to get photos of freak wave activity. He was positioned on a cliff 90 feet above sea level when a freak wave came and swept him away.

Living here in the middle of the North American continent, I feel pretty insulated from the impact of freak waves. Hummm…..now, if I could just figure out how to create one in the Science Museum’s wave tank

Jun
03
2006


Mount Everest at Sunset: With ten confirmed deaths already this year, it's the second-deadliest climbing season on record for Mount Everest. What can be done to make climbers safer?
In the world of back-country hiking, the motto always is “Leave the area cleaner than you found it.” But that doesn’t seem to be the case with trekkers up Mount Everest these days.

And what they’re leaving behind is other frozen hikers.

This year’s climbing season on the world’s largest mountain is shaping up to be one of the deadliest. And the situation has people getting up in arms over the ethics involved with high-altitude, high-risk mountain climbing.

So far this year, there have been 10 confirmed fatalities on Everest, making it the second-deadliest climbing season on record. In 1996, 19 climbers died. All totaled, about 200 climbers have succumbed to Everest’s low oxygen and frigid temperatures in the 50 years climbers have bee summiting it.

But what really has people talking about the situation this year is that in the case of one of the fatalities, about 40 other climbers passed by the nearly frozen hiker, leaving him to die. Some ask, “How could they do that?”

First off, the elevation at the top of Everest is so high, it’s very risky if not impossible for helicopters to get there. Also, communication by phone or radio is extremely limited at those heights.

Due to the unforgiving nature of the top of the mountain, some climbers say it’s too risky to spend time and energy on a rescue mission that may very likely result in a death anyway. Time, oxygen and food are so limited at that altitude, losing them through the efforts of a rescue mission might lead others to die.

Some climbers have the attitude that they all assume huge risks to venture out on such a climb. If someone’s luck turns bad, they knew what they were getting into and shouldn’t expect extraordinary help.

Critics of those trains of thought point out that many climbers spent lots of money, $10,000 to $40,000, to pursue their dream. At that cost, they’re not willing to let their personal ambitions fade away to try to help someone else. They claim that many of these climbers don’t have the mountaineering skills necessary for success.

Also, they’re very concerned that Everest is becoming littered with corpses, used oxygen tanks and other climbing gear.

Do you think this is a crisis in need of some kind of fix? What alternatives might there be to help ease this situation? Share your ideas here by posting your comments.

Jun
02
2006

On May 27, a powerful earthquake—centered about ten miles southeast of Yogyakarta—shook Java, Indonesia. It destroyed more than 135,000 houses, leaving 200,000 people homeless, and it killed at least 6234 people, injuring another 46,000. And volcanic activity on nearby Mount Merapi has tripled since the quake, sparking fears of an eruption.

The "ring of fire"

The continents rest on large plates of rock that are slowly moving around the surface of the Earth. Indonesia, a nation of more than 18,000 islands, experiences a lot of earthquakes and volcanic eruptions because it sits along the “ring of fire”—the Pacific Ocean’s zone of active volcanoes and tectonic faults.

Just south of Java, the Australian plate is moving north at two and a half inches each year. Where the Australia plate collides with the Sunda plate—which includes Java—the Australia plate slips under the Java plate in a process geologists call subduction.

Pressure builds up along the fault lines where the plates meet. When the rocks separating the plates suddenly give way, the ground shakes and buckles in what we call an earthquake. Volcanoes are formed when the subducted rock melts and returns to the surface as magma.

How strong was this earthquake?

The United States Geological Survey says the quake measured 6.3 on the Richter scale. This quake didn’t cause tsunamis like the big earthquake in December 2004. But it was shallow—only 6 miles underground—which made the shaking on the surface more intense than other quakes of the same magnitude. And the quake struck at 5:54 am local time, trapping many people in their homes.

How did this earthquake compare to others?

  • October 8, 2005: Pakistani Kashmir
    Magnitude 7.6, 30,000 killed
  • March 28, 2005: Sumatra, Indonesia
    Magnitude 8.7, up to 1,000 killed
  • December 26, 2004: Sumatra, Indonesia
    Magnitude 9.0, more than 176,000 people killed by earthquake and resulting tsunami
  • December 26, 2003: Bam, Iran
    Magnitude 6.5, more than 26,000 killed
  • May 21, 2003: northern Algeria
    Magnitude 6.8, nearly 2,300 killed