THE HELIOSPHERE
The region of space governed by the Sun is called the heliosphere. This area is filled with plasma from the Sun in the form of the solar wind. Beyond the heliosphere, interstellar space exists, and it is filled with plasma from other stars. The heliosphere marks the division between the solar plasma and the interstellar plasma. It is the area where the pressure of the solar wind equals the pressure of the interstellar medium.
I understand that all this is hard to picture in your mind, but try to imagine the heliosphere as a kind of bubble that contains the solar system. It's a magnetic sphere that reaches beyond Pluto and is caused by the solar winds.
NASA's Cassini spacecraft suggests that the heliosphere may not possess the comet-like shape that scientists thought, but instead is more like a big, round bubble. This changes what they have thought for the past fifty years. The images indicate that the solar wind's interaction with the interstellar medium is instead more significantly controlled by particle pressure and the energy density of the magnetic field.
The Voyager spacecraft(s) have crossed the termination shock several time as it moves in and out from the Sun. This is due partly because of the pressure of the solar wind, which can increase or decrease as it flows from the Sun. Before reaching the heliosphere the solar wind is slowed from supersonic to subsonic speed, and this creates a shockwave called the termination shock.
So all this makes me wonder, when we have one, can our spacecraft travel safely beyond the heliosphere and withstand the termination shock? Can we protect the lives of the people inside? Of course, this means we are leaving our solar system. This is something to think about, one more thing to consider in space travel.
More information at http://www.universetoday.com/32519/heliosphere/
references: www.universetoday.com, www.cosmos4kids.com/files/solsyst2, http://helios.gsfc.nasa.gov/heliosph.html, www.sciencedaily.com/releases/2009/10/091016101807.htm
Sunday, August 18, 2013
Thursday, June 20, 2013
Finding Earth-like Planets
Astronomers are actively searching for Earth-like planets outside of our solar system - or as they say, exoplanets. Most of the planets they have found so far are enormous, at least the size of Jupiter. It's much more difficult to find planets as small as Earth. Now, scientists believe that 6 percent of red dwarf stars have Earth-sized planets located at the right distance from the star to be potentially habitable.
Our Milky Way Galaxy may be home to approximately two billion Earth-like planets. This is based on a new study and initial data from NASA's Kepler space telescope. Based on Kepler's findings so far, the studies are up to 2.7 percent of all sun like stars in the Milky Way host so-called Earth like worlds. As of this February, Kepler has confirmed 15 new planets and found an additional 1,235 planet candidates, including a small planet outside of our solar system. Kepler will collect data for a minimum of three and a half years and plans to undertake a more complete census at a later date.
What I have found in my research is that the closest Earth-like planet astronomers have reported may be only 13 light years away - or approximately 77 trillion miles. They have not identified it yet, but feel it should be there based on the teams' study of red dwarf stars. Most of us have heard of Gilese 581, a red dwarf star in the constellation Libra that lies about 20.5 light years from Earth. The European Southern Observatory (ESO) telescope in Chile has discovered Gilese 581d, a planet they speculate to have a rocky core, an icy layer, and a liquid ocean at the surface with an atmosphere. At this stage they can only speculate but it is possible. Gilese 581e is another planet looking much like Earth, except that it is very hot because it so close to its host star.
NASA and the scientists working on this project favor Kepler-22b which was discovered about 600 light years from us, in another solar system. They view this planet as having the best chances of life because of the striking similarities to Earth. Its surface is a comfortable 72F and the star it orbits can almost be a twin of our sun. Although it is 2.4 times bigger than Earth, scientists suspect it probably has water and land making it a great target for life. Now scientists have found other planets in in the Kepler-22 group which makes this a study of 3 or 4 planets that may all be Earth-like.
So how do scientists find these planets? That's a great question - there are four ways:
The first is called the "radial velocity method": This is when stars are pulled back and forth by the gravitational pull of the planet. This allows them to measure the shift in the light frequency.
Another method is "positional astronomy": This is when they take a measurement of the tiny shift in a star's location on the sky which is caused by the gravitational pull of a planet. They can determine mass and orbit as well.
The "transit method": Scientists have found that a planet blocks out a small portion of the star's light when it passes directly between a star and the observer. They will watch it to confirm the fluctuations in the star's light. This means a planet is orbiting that star.
Last is the "gravitational microlensing" method: This comes from Einstein's thoughts regarding his theory of relativity. I like this ~ gravity bends space. The planet's gravity will act like a lens for a short time to focus light from a star. This works well with more distant stars. It seems to warp space to cause a noticeable increase in brightness and a change in position of the star.
I never said it's easy to find planets outside of our solar system. Most of them are very far away, but recently astronomers have found a planet that orbits a star called Alpha Centauri B, which is our closest star about 4 light years away or 23.5 trillion miles. It is a rocky planet but may be too hot to sustain life. Any time we can measure the distance in space using miles (even if it is trillions) this would be termed as being in our neighborhood.
There's a plan to search in more depth for Earth-like planets: http://www.dailygalaxy.com/my_weblog/2013/04/kepler-mission-20-to-launch-in-2017-thousands-of-neigboring-earth-like-alien-planets-to-be-identifie.html
My references include: NASA online, Daily Planet, StarDate.org, and dailygalaxy.com.
Our Milky Way Galaxy may be home to approximately two billion Earth-like planets. This is based on a new study and initial data from NASA's Kepler space telescope. Based on Kepler's findings so far, the studies are up to 2.7 percent of all sun like stars in the Milky Way host so-called Earth like worlds. As of this February, Kepler has confirmed 15 new planets and found an additional 1,235 planet candidates, including a small planet outside of our solar system. Kepler will collect data for a minimum of three and a half years and plans to undertake a more complete census at a later date.
What I have found in my research is that the closest Earth-like planet astronomers have reported may be only 13 light years away - or approximately 77 trillion miles. They have not identified it yet, but feel it should be there based on the teams' study of red dwarf stars. Most of us have heard of Gilese 581, a red dwarf star in the constellation Libra that lies about 20.5 light years from Earth. The European Southern Observatory (ESO) telescope in Chile has discovered Gilese 581d, a planet they speculate to have a rocky core, an icy layer, and a liquid ocean at the surface with an atmosphere. At this stage they can only speculate but it is possible. Gilese 581e is another planet looking much like Earth, except that it is very hot because it so close to its host star.
NASA and the scientists working on this project favor Kepler-22b which was discovered about 600 light years from us, in another solar system. They view this planet as having the best chances of life because of the striking similarities to Earth. Its surface is a comfortable 72F and the star it orbits can almost be a twin of our sun. Although it is 2.4 times bigger than Earth, scientists suspect it probably has water and land making it a great target for life. Now scientists have found other planets in in the Kepler-22 group which makes this a study of 3 or 4 planets that may all be Earth-like.
So how do scientists find these planets? That's a great question - there are four ways:
The first is called the "radial velocity method": This is when stars are pulled back and forth by the gravitational pull of the planet. This allows them to measure the shift in the light frequency.
Another method is "positional astronomy": This is when they take a measurement of the tiny shift in a star's location on the sky which is caused by the gravitational pull of a planet. They can determine mass and orbit as well.
The "transit method": Scientists have found that a planet blocks out a small portion of the star's light when it passes directly between a star and the observer. They will watch it to confirm the fluctuations in the star's light. This means a planet is orbiting that star.
Last is the "gravitational microlensing" method: This comes from Einstein's thoughts regarding his theory of relativity. I like this ~ gravity bends space. The planet's gravity will act like a lens for a short time to focus light from a star. This works well with more distant stars. It seems to warp space to cause a noticeable increase in brightness and a change in position of the star.
I never said it's easy to find planets outside of our solar system. Most of them are very far away, but recently astronomers have found a planet that orbits a star called Alpha Centauri B, which is our closest star about 4 light years away or 23.5 trillion miles. It is a rocky planet but may be too hot to sustain life. Any time we can measure the distance in space using miles (even if it is trillions) this would be termed as being in our neighborhood.
There's a plan to search in more depth for Earth-like planets: http://www.dailygalaxy.com/my_weblog/2013/04/kepler-mission-20-to-launch-in-2017-thousands-of-neigboring-earth-like-alien-planets-to-be-identifie.html
My references include: NASA online, Daily Planet, StarDate.org, and dailygalaxy.com.
Saturday, May 4, 2013
WHAT IS CURIOSITY UP TO NOW?
Since its landing at the Gale Crater, Mars, Curiosity is now trekking westward from Glenelg to Yellowknife Bay and Point Lake. Did you know that the rover team is on Martian time? They are tracking Curiosity for 24 hours, 39 minutes, and 35 seconds per sol (day), and this will last for one Martian year or 687 sols. Mars gets chilly, the temperature is about -130F degrees, and windy with wind gusts to 90mph. Oh and the rover only covers a distance of about 300 ft in a day.
In retrospect, the science team decided to name the exact landing spot “Bradbury Landing.” Glenelg was chosen because it’s a site that appears to contain three different rock types. Of interest is the sedimentary rock that we all know is formed by materials deposited by flowing water. What is indicated by the other various colors of rock in that area is yet unknown. It seems that what we do know is that Mars had an environment that was able to support water on its surface in the past.
As a matter of fact I came across this statement, “We have found a habitable environment that is so benign and supportive of life that probably, if this water was around and you had been on the planet, you would have been able to drink it,” said John Grotzinger of Caltech in Pasadena.
It has also been confirmed that the rock drilling results reveal elements found on Earth and clay containing not much salt which would indicate a lake may have existed there before. Remember, the reason for this mission is to “search for organic life on Mars,” over a two year period.
Well, looks like we’ve determined time again that water did exist on Mars. Don’t get me wrong, that’s great news. But what else may have existed on Mars? Any life forms, no matter how small, are they like any life form on Earth? Perhaps they are completely alien. Now that would be something for discussion.
But how about this news – radiation levels on Mars now are comparable to that of the same levels the astronauts are experiencing on the International Space Station. What this means is that longer term surface exploration is possible, outside the possibility of solar eruptions or surface sandstorms.
This gives us all something to think about over the next decade. Personally, bar any yet unknown factors that would kill a manned-mission there, I think scientists are planning a visit if not colonization. We need to focus on that warp speed theory, so we can get to Mars in minutes, not several months or years. There is still a lot of work to be done.
You can check NASA’s map of Mars for the current location of Curiosity here:
References: NASA, Universe Today, and Space.com
Friday, April 12, 2013
THE NEBULA: WHERE STARS ARE BORN
In astronomy a nebula is defined as, "A diffuse cloud of particles and gases, mainly hydrogen that is visible either as a hazy patch of light, and either by emission or reflection, or an irregular dark region against a brighter background." That's a pretty good definition but when I see one, I define it as a breathtaking sight of colors and shapes in varying degrees of brilliance. I'm sure you have seen some of the images taken by the Hubble telescope over the years.
Did you know there are different kinds of nebulae? Yes, and some of the prominent ones are:
Stellar Nursery: This is a nebula where star formation is occurring. I like to refer to it as a "star nursery," as some scientists do. These nebulae are often illuminated by ultraviolet light which is emitted from the newborn stars. The Eagle nebula is a good example of a star nursery. But our closest star nursery is located in the constellation Orion, located only 1,350 light years from Earth. Just with the naked eye, (and when conditions are right), you can see a hazy patch by Orion's "sword," which is located just below the three stars in his belt. This is the Orion Nebula. With binoculars or a telescope you can see it even better.
Planetary Nebula: This is formed by a shell of gas which was ejected from certain kinds of intensely hot stars, as red giants or super giants. When these stars explode, only the super hot core remains. The first one, called the "Dumbbell Nebula" was discovered in 1764. These nebulae have nothing to do with planets.
Emission Nebula: This type of nebula glows because it is emitting light energy. The reddish light is created by the hydrogen atoms that are formed when electrons and protons combine. This process is caused when a very hot star stirs up a cloud of hydrogen gas. The "Horsehead Nebula" is in front of an emission nebula which illuminates the outline of the horse head.
Reflection Nebula: Is a type of nebula that glows as the dust in it reflects the light of nearby stars. These nebulae are often bluish in color because blue light is more efficiently reflected than red light. An example of one surrounds the Pleiades Cluster.
Ring Nebula: Just as the name implies, the Ring Nebula is a massive cloud of dust and gas that is shaped like a ring. There is a good example of one in Lyra, which is 2,000 light years from Earth.
Since there are so many of these scattered throughout the universe I like to visit the Hubble site to look at some of the images in their library. Looking at these is an awe-inspiring moment of how vast the universe really is and how tiny we are.
Please visit Hubble at http://hubblesite.org/gallery/album/nebula/
Have your own awe-inspired moment.
Did you know there are different kinds of nebulae? Yes, and some of the prominent ones are:
Stellar Nursery: This is a nebula where star formation is occurring. I like to refer to it as a "star nursery," as some scientists do. These nebulae are often illuminated by ultraviolet light which is emitted from the newborn stars. The Eagle nebula is a good example of a star nursery. But our closest star nursery is located in the constellation Orion, located only 1,350 light years from Earth. Just with the naked eye, (and when conditions are right), you can see a hazy patch by Orion's "sword," which is located just below the three stars in his belt. This is the Orion Nebula. With binoculars or a telescope you can see it even better.
Planetary Nebula: This is formed by a shell of gas which was ejected from certain kinds of intensely hot stars, as red giants or super giants. When these stars explode, only the super hot core remains. The first one, called the "Dumbbell Nebula" was discovered in 1764. These nebulae have nothing to do with planets.
Emission Nebula: This type of nebula glows because it is emitting light energy. The reddish light is created by the hydrogen atoms that are formed when electrons and protons combine. This process is caused when a very hot star stirs up a cloud of hydrogen gas. The "Horsehead Nebula" is in front of an emission nebula which illuminates the outline of the horse head.
Reflection Nebula: Is a type of nebula that glows as the dust in it reflects the light of nearby stars. These nebulae are often bluish in color because blue light is more efficiently reflected than red light. An example of one surrounds the Pleiades Cluster.
Ring Nebula: Just as the name implies, the Ring Nebula is a massive cloud of dust and gas that is shaped like a ring. There is a good example of one in Lyra, which is 2,000 light years from Earth.
Since there are so many of these scattered throughout the universe I like to visit the Hubble site to look at some of the images in their library. Looking at these is an awe-inspiring moment of how vast the universe really is and how tiny we are.
Please visit Hubble at http://hubblesite.org/gallery/album/nebula/
Have your own awe-inspired moment.
Sunday, March 24, 2013
What is a Quasar? What is the Huge-LQG?
In my last post I wrote about Pulsars which are neutron stars. They are the rapidly rotating compacted remains of a dead star, that emit a stream of dust and energy in the form of light. When viewed from Earth, they appear to be pulsating.
So is a Quasar, more stars? Not exactly. The word quasar means, "quasi-stellar object" or "quasi-stellar radio source." They are similar to stars because they are extremely luminous. However, quasars are in a class of extragalactic objects that emit an immense amount of energy, in the form of light. This is infrared radiation coming from a compact source. Meaning they are high redshift sources of electromagnetic energy. They have a light signature and an energy signature. I know it sounds complicated. Maybe it's because quasars are the most complicated and interesting stellar objects in our universe.
Recently, the Huge-LQG (Large Quasar Group) has been discovered. It's a group of 73 quasars, which at some point were thought to be at the center of their own respective galaxies. It stretches 4 billion light years across (at its longest point). Our Milky Way Galaxy is only a small 100,000 light years across. To attempt to make some sense of the scale of this huge quasar group, imagine that it would take "tens of thousands of our own Milky Ways" to equal the enormous size of the Huge-LQG.
What does this all mean? There's a little something called the "cosmological principle", which states,"if viewed on a sufficiently large scale, the properties of the universe are the same for all observers." So, us little Earthlings thought that if you look out into the universe from any point, (on Earth), then space should look the same no matter the direction from which you're looking. But, now we have learned this object is simply too large to fit into the confines of the cosmological principle. It appears that our little corner of the universe, what we can see of it, is unique to itself.
Don't you wonder what else is out there? We should feel like a fraction of a fraction of a fraction of a grain of sand. We are only beginning to learn and understand this vast universe...and we have a long way to go!
Here is a link to the quasar cluster, "Biggest Thing in Universe Found."
http://news.nationalgeographic.com/news/2013/01/130111-quasar-biggest-thing-universe-science-space-evolution/
So is a Quasar, more stars? Not exactly. The word quasar means, "quasi-stellar object" or "quasi-stellar radio source." They are similar to stars because they are extremely luminous. However, quasars are in a class of extragalactic objects that emit an immense amount of energy, in the form of light. This is infrared radiation coming from a compact source. Meaning they are high redshift sources of electromagnetic energy. They have a light signature and an energy signature. I know it sounds complicated. Maybe it's because quasars are the most complicated and interesting stellar objects in our universe.
Recently, the Huge-LQG (Large Quasar Group) has been discovered. It's a group of 73 quasars, which at some point were thought to be at the center of their own respective galaxies. It stretches 4 billion light years across (at its longest point). Our Milky Way Galaxy is only a small 100,000 light years across. To attempt to make some sense of the scale of this huge quasar group, imagine that it would take "tens of thousands of our own Milky Ways" to equal the enormous size of the Huge-LQG.
What does this all mean? There's a little something called the "cosmological principle", which states,"if viewed on a sufficiently large scale, the properties of the universe are the same for all observers." So, us little Earthlings thought that if you look out into the universe from any point, (on Earth), then space should look the same no matter the direction from which you're looking. But, now we have learned this object is simply too large to fit into the confines of the cosmological principle. It appears that our little corner of the universe, what we can see of it, is unique to itself.
Don't you wonder what else is out there? We should feel like a fraction of a fraction of a fraction of a grain of sand. We are only beginning to learn and understand this vast universe...and we have a long way to go!
Here is a link to the quasar cluster, "Biggest Thing in Universe Found."
http://news.nationalgeographic.com/news/2013/01/130111-quasar-biggest-thing-universe-science-space-evolution/
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