31
Open Chat / We are popular!!!!!
« on: March 14, 2008, 02:59:46 PM »
[ATTACH]616[/ATTACH]
This is really cool. Who knew?
? :Score-101010:
This is really cool. Who knew?
? :Score-101010:
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32
New member welcome / Greetings from WS2L
« on: March 11, 2008, 08:41:55 PM »
Greetings and salutations. Hope you enjoy this site as much as I have. Welcome!!!!!!!!!!!!!
33
Open Chat / A hole of nothing???
« on: March 08, 2008, 09:02:57 PM »
In August 2007, scientists from the University of Minnesota published an astonishing finding in the Astrophysical Journal. The universe, they declared, had a hole in it -- a hole far bigger than anything scientists have ever seen or expected. This "hole" spans almost one billion light years and is six to 10 billion light years from Earth, in the Eridanus constellation [source: Daily Tech]. (For reference, one light year measures about six trillion miles.)
What makes this vast area of the universe a hole? The area shows almost no signs of cosmic matter, meaning no stars, planets, solar systems or clouds of cosmic dust. Researchers couldn\'t even find dark matter, which is invisible but measurable by its gravitational pull. There were also no signs of black holes that might have gobbled up the matter once present in the region.
The hole was initially detected by a NASA program studying the spread of radiation emitted from the Big Bang, which scientists believe spawned our universe. It was then further examined using information gleaned from the Very Large Array (VLA) telescope, used in the NRAO VLA Sky Survey Project to study large sections of the visible sky.
One researcher described the find as "not normal," going against computer simulations and past studies [source: Yahoo News]. Other such holes, also known as voids, have been found before, but this find is by far the largest. Other voids amount to around 1/1000th the size of this one, while scientists once observed a void as close as two million light years away -- practically down the street in cosmic terms [source: CNN.com].
Astronomer Brent Tully told the Associated Press that galactic voids in all likelihood develop because regions of space with high mass pull matter from less massive areas [source: CNN.com]. Over billions of years, a region can lose most of its mass to a massive neighbor. In the case of this giant void, further studies may reveal some matter in the region, but it would still be far less than what is found in "normal" parts of space.
Earlier we said that the void was first discovered through a NASA program examining radiation stemming from the Big Bang. On the next page, we\'ll take a closer look at that program and how scientists can look far back into the universe\'s history -- almost to its beginnings -- in order to make discoveries like this one.
On June 30, 2001, NASA launched the Wilkinson Microwave Anisotropy Probe (WMAP), a satellite that has since been used to map cosmic microwave background (CMB) radiation. CMB radiation is billions of years old, a byproduct of the Big Bang that scientists detect in the form of radio waves. CMB radiation yields insights into the early history of the universe, showing what it looked like when it was as young as a few hundred thousand years old. And by examining the spread of CMB radiation, scientists can find out how the universe has developed since the Big Bang and how it will continue to develop -- or even end.
Until the giant galactic void was further studied by the University of Minnesota researchers, it was known as the "WMAP Cold Spot" because NASA scientists measured colder temperatures in the region than in surrounding areas. The temperature difference only amounted to a few millionths of a degree, but that was enough to indicate something was much different about that section of space.
In order to understand why galactic voids show up as cooler, it\'s important to consider the role of dark energy. Like dark matter, dark energy is prevalent throughout the known universe. But in an area lacking dark energy, photons (originating from the Big Bang) pick up energy from objects as they approach them. As they move away, the gravitational force of those objects takes that energy back. The result is no net change in energy.
An area where dark energy is present works differently. When photons pass through space containing dark energy, the dark energy gives the photons energy. Consequently areas with a lot of photons and dark energy show up on scans as more energetic and hotter. Photons lose some of their energy if they pass through a galactic void lacking in dark energy. Those areas in turn emit cooler radiation. A giant void where little matter or dark energy is present, like the WMAP Cold Spot, causes significant drops in radiation temperature.
Both dark matter and dark energy remain rather mysterious to scientists. Much scientific research is underway to examine these substances and their roles in various cosmic processes. Dark energy may be even less understood than dark matter, but scientists do know that dark energy serves an important role in accelerating the universe\'s growth, especially in recent cosmological history. We also know that photons passing through dark energy allow for the kind of energy changes that produce varying temperatures that are in turn represented in the CMB map. Examining these temperature fluctuations allows scientists to learn how the universe is growing and developing. And considering that dark energy is the most common type of energy in the universe, it should continue to occupy a prominent role in cosmological research for years to come.
What makes this vast area of the universe a hole? The area shows almost no signs of cosmic matter, meaning no stars, planets, solar systems or clouds of cosmic dust. Researchers couldn\'t even find dark matter, which is invisible but measurable by its gravitational pull. There were also no signs of black holes that might have gobbled up the matter once present in the region.
The hole was initially detected by a NASA program studying the spread of radiation emitted from the Big Bang, which scientists believe spawned our universe. It was then further examined using information gleaned from the Very Large Array (VLA) telescope, used in the NRAO VLA Sky Survey Project to study large sections of the visible sky.
One researcher described the find as "not normal," going against computer simulations and past studies [source: Yahoo News]. Other such holes, also known as voids, have been found before, but this find is by far the largest. Other voids amount to around 1/1000th the size of this one, while scientists once observed a void as close as two million light years away -- practically down the street in cosmic terms [source: CNN.com].
Astronomer Brent Tully told the Associated Press that galactic voids in all likelihood develop because regions of space with high mass pull matter from less massive areas [source: CNN.com]. Over billions of years, a region can lose most of its mass to a massive neighbor. In the case of this giant void, further studies may reveal some matter in the region, but it would still be far less than what is found in "normal" parts of space.
Earlier we said that the void was first discovered through a NASA program examining radiation stemming from the Big Bang. On the next page, we\'ll take a closer look at that program and how scientists can look far back into the universe\'s history -- almost to its beginnings -- in order to make discoveries like this one.
On June 30, 2001, NASA launched the Wilkinson Microwave Anisotropy Probe (WMAP), a satellite that has since been used to map cosmic microwave background (CMB) radiation. CMB radiation is billions of years old, a byproduct of the Big Bang that scientists detect in the form of radio waves. CMB radiation yields insights into the early history of the universe, showing what it looked like when it was as young as a few hundred thousand years old. And by examining the spread of CMB radiation, scientists can find out how the universe has developed since the Big Bang and how it will continue to develop -- or even end.
Until the giant galactic void was further studied by the University of Minnesota researchers, it was known as the "WMAP Cold Spot" because NASA scientists measured colder temperatures in the region than in surrounding areas. The temperature difference only amounted to a few millionths of a degree, but that was enough to indicate something was much different about that section of space.
In order to understand why galactic voids show up as cooler, it\'s important to consider the role of dark energy. Like dark matter, dark energy is prevalent throughout the known universe. But in an area lacking dark energy, photons (originating from the Big Bang) pick up energy from objects as they approach them. As they move away, the gravitational force of those objects takes that energy back. The result is no net change in energy.
An area where dark energy is present works differently. When photons pass through space containing dark energy, the dark energy gives the photons energy. Consequently areas with a lot of photons and dark energy show up on scans as more energetic and hotter. Photons lose some of their energy if they pass through a galactic void lacking in dark energy. Those areas in turn emit cooler radiation. A giant void where little matter or dark energy is present, like the WMAP Cold Spot, causes significant drops in radiation temperature.
Both dark matter and dark energy remain rather mysterious to scientists. Much scientific research is underway to examine these substances and their roles in various cosmic processes. Dark energy may be even less understood than dark matter, but scientists do know that dark energy serves an important role in accelerating the universe\'s growth, especially in recent cosmological history. We also know that photons passing through dark energy allow for the kind of energy changes that produce varying temperatures that are in turn represented in the CMB map. Examining these temperature fluctuations allows scientists to learn how the universe is growing and developing. And considering that dark energy is the most common type of energy in the universe, it should continue to occupy a prominent role in cosmological research for years to come.
34
Open Chat / Another Earth??
« on: March 07, 2008, 08:32:50 PM »
Earth may have a twin orbiting one of our nearest stellar neighbors, a new study suggests.
University of California, Santa Cruz graduate student Javiera Guedes used computer simulations of planet formation to show that terrestrial planets are likely to have formed around one of the stars in the Alpha Centauri star system, our closest stellar neighbors.
Guedes\' model showed planets forming around the star Alpha Centauri B (its sister star, Proxima Centauri, is actually our nearest neighbor) in what is called the "habitable zone," or the region around a star where liquid water can exist on a planet\'s surface.
The model also showed that if such planets do in fact exist, we should be able to see them with a dedicated telescope.
"If they exist, we can observe them," Guedes said.
Guedes\' study has been accepted for publication in the Astrophysical Journal.
A likely candidate
Astronomers have for some time pinned the Alpha Centauri system as one that was likely to form planets, said study co-author Gregory Laughlin, a UCSC professor.
"I think that there\'s been a good line of evidence over the past decade or so," Laughlin told SPACE.com.
Several factors mark the system, particularly Alpha Centauri B as friendly to planet formation, Laughlin said. The metallicity of Alpha Centauri B (or how much of its matter is made up of elements heavier than hydrogen and helium) is higher than our Sun\'s, so there would be plenty of heavier-mass material for planets to form from, he said.
Also, because the planet is a triple star system, the processes that form large Jupiter-mass gas giants, which account for most of the extrasolar planets found so far, would be suppressed. So it would be more likely for the system to produce terrestrial planets.
Laughlin also noted that a number of factors make Alpha Centauri B a good candidate for astronomers to actually detect an Earth-sized terrestrial planet.
Training telescopes
The Doppler detection method, which has revealed the majority of the 228 known extrasolar planets, measures shifts in the light from a star to detect the tiny wobble induced by the gravitational tug of an orbiting planet.
Because Alpha Centauri B is so bright and nearby, detecting a small terrestrial planet\'s miniscule wobble would be that much easier. Also, its position high in the sky of the Southern Hemisphere means it is observable for most of the year, just as the Big Dipper is observable for most of the year in the Northern Hemisphere.
According to Laughlin, five years of observations using a dedicated telescope would be needed to detect an Earth-like planet around Alpha Centauri B. If astronomers do dedicate substantial resources to detecting an Earth-like planet, this is the star to focus on, he added.
"We\'re advocating that there\'s a strong possibility a planet could be there," he said.
Other stars are thought to harbor Earth-like planets, and solar systems like ours are starting to be found. Astromoners announced last month the discovery of a solar system with striking similarities to ours.
If such a planet is found, spacecraft, such as the proposed Terrestrial Planet Finder, could be launched to find out more information about the world, such as whether or not it had water on its surface, Laughlin said.
Study co-author Debra Fischer of San Francisco State University is leading an observational program to intensively monitor Alpha Centauri A and B using the 1.5-meter telescope at the Cerro Tololo Inter-American Observatory in Chile. The researchers hope to detect real planets similar to the ones that emerged in the computer simulations.
"I think the planets are there, and it\'s worth a try to have a look," Laughlin said.
Now this is very interesting. Perhaps we are not alone in this vast emptiness known as the universe.
University of California, Santa Cruz graduate student Javiera Guedes used computer simulations of planet formation to show that terrestrial planets are likely to have formed around one of the stars in the Alpha Centauri star system, our closest stellar neighbors.
Guedes\' model showed planets forming around the star Alpha Centauri B (its sister star, Proxima Centauri, is actually our nearest neighbor) in what is called the "habitable zone," or the region around a star where liquid water can exist on a planet\'s surface.
The model also showed that if such planets do in fact exist, we should be able to see them with a dedicated telescope.
"If they exist, we can observe them," Guedes said.
Guedes\' study has been accepted for publication in the Astrophysical Journal.
A likely candidate
Astronomers have for some time pinned the Alpha Centauri system as one that was likely to form planets, said study co-author Gregory Laughlin, a UCSC professor.
"I think that there\'s been a good line of evidence over the past decade or so," Laughlin told SPACE.com.
Several factors mark the system, particularly Alpha Centauri B as friendly to planet formation, Laughlin said. The metallicity of Alpha Centauri B (or how much of its matter is made up of elements heavier than hydrogen and helium) is higher than our Sun\'s, so there would be plenty of heavier-mass material for planets to form from, he said.
Also, because the planet is a triple star system, the processes that form large Jupiter-mass gas giants, which account for most of the extrasolar planets found so far, would be suppressed. So it would be more likely for the system to produce terrestrial planets.
Laughlin also noted that a number of factors make Alpha Centauri B a good candidate for astronomers to actually detect an Earth-sized terrestrial planet.
Training telescopes
The Doppler detection method, which has revealed the majority of the 228 known extrasolar planets, measures shifts in the light from a star to detect the tiny wobble induced by the gravitational tug of an orbiting planet.
Because Alpha Centauri B is so bright and nearby, detecting a small terrestrial planet\'s miniscule wobble would be that much easier. Also, its position high in the sky of the Southern Hemisphere means it is observable for most of the year, just as the Big Dipper is observable for most of the year in the Northern Hemisphere.
According to Laughlin, five years of observations using a dedicated telescope would be needed to detect an Earth-like planet around Alpha Centauri B. If astronomers do dedicate substantial resources to detecting an Earth-like planet, this is the star to focus on, he added.
"We\'re advocating that there\'s a strong possibility a planet could be there," he said.
Other stars are thought to harbor Earth-like planets, and solar systems like ours are starting to be found. Astromoners announced last month the discovery of a solar system with striking similarities to ours.
If such a planet is found, spacecraft, such as the proposed Terrestrial Planet Finder, could be launched to find out more information about the world, such as whether or not it had water on its surface, Laughlin said.
Study co-author Debra Fischer of San Francisco State University is leading an observational program to intensively monitor Alpha Centauri A and B using the 1.5-meter telescope at the Cerro Tololo Inter-American Observatory in Chile. The researchers hope to detect real planets similar to the ones that emerged in the computer simulations.
"I think the planets are there, and it\'s worth a try to have a look," Laughlin said.
Now this is very interesting. Perhaps we are not alone in this vast emptiness known as the universe.
35
Been looking for one of these ever since I regretfully sold mine years ago. Its a Dual band HT and must have then MH 29 LCD speaker mic and drop in mobile craddle/charger. If anyone has one of these in excellent order with a battery that holds a charge, let me know. Perhaps we can work out a deal.
36
Oscar Satellite talk / Satscape
« on: March 05, 2008, 09:35:07 PM »
This is a really cool program. I use it to track AO-27 and other sats. Give it a try!!!!
http://[/I][/SIZE]http://www.satscape.co.uk/
http://[/I][/SIZE]http://www.satscape.co.uk/
37
Amateur Radio News and Activities / Hamfests
« on: March 05, 2008, 09:25:06 PM »
Wish there were hamfest close to my local. If there are, I have not heard of any.
39
New member welcome / Welcome w8kyz
« on: March 05, 2008, 09:16:03 PM »
Greetings and salutations. Welcome to the forums
40
Announcements / Name This Site
« on: March 04, 2008, 10:13:27 AM »
Silverado Hams...... I dunno just throwing a name out there HIHI :p
41
Entertainment / Terminator: Sara Conor Chronicals
« on: March 04, 2008, 10:04:26 AM »
Arrrrggghhhhh! Someone blew up Cameron. And no previews. Wonder whats gonna happen now and who was it that planted the bomb in her suv. I didnt recognise the guy but Im thinking its another Terminator. Will have to wait and see when the new season starts........
42
New member welcome / Kj4cjv
« on: March 03, 2008, 10:18:31 PM »
Greetings n salutations. Welcome to our home and the hobby of ham radio! 
43
Entertainment / Beowulf
« on: March 02, 2008, 08:28:03 PM »
I just saw this movie and Im here to tell ya, EXCELLENT. If you like movies that resemble EQ2, then you\'re gonna love this one. I highly reccomend watching it. :fam05:
44
Software Talk / Hamsphere
« on: March 02, 2008, 08:20:44 PM »
Another program I came across is EQ-100. I DL\'D it but still cant get it to run. Runtime error or something like that :shrug: