Earths Magnetic Field About to Flip?

[A-L-E-X]

I instantly built a mental picture of a person walking down the sidewalk and then you hear the sound of a ball hitting a bat and the person goes down flat on their bum, seemingly for no reason at all

I mean, think of the force of a 60 mph baseball concentrated into a single proton lol. Im surprised that thing didnt drill a hole through the earth.

[aslkahuna]

Eta Carina might be a different story, however. During its last outburst as a nova it was actually the most intrinsically luminous star in the sky.

Actually, Eta Carinae's last outburst was more of a mass loss event rather than a nova which is a mass transfer event resulting in a "modest" explosion. In that regard, novae are similar but much less intense than a Type Ia Supernova which results when a star transfers enough mass to a white dwarf companion (or two WD's merge) to push it over the Chandrasekhar limit at which point the entire white dwarf detonates. Eta Carinae is far more massive than the progenitor of the Crab Supernova which would have been a regular Type II event or core collapse of a star of 8-15 Solar masses-this is confirmed by the presence of the neutron star which is the collapsed core at about 1.6 Solar mass. Eta Carinae depending upon how much mass it loses before collapse could be a hypernova where the core immediately collapses into a Black Hole. In order for the GRB to be Earth Directed the magnetic axis of Eta would have to point towards us.

About the SAA, the main reason that Hubble does not take observations when transitting the South Atlantic Anomaly is that it is among a class of satellites that use magnetic torquers for attitude control and they don't work so well when the satellite is in the SAA. Another problem in the anomaly involves Van Allen dumping which occurs during the late decay phase of a Geomagnetic storm. When that occurs the normal flux of electrons with energies > 2 MeV at satellite altitudes increases sharply and stays high for a period of days (as it currently is now). The problem for a spacecraft in this situation unlike the one with high energy protons (bit flips or Single Event Upsets), is spacecraft charging where a strong electrical charge builds up on the surface of the spacecraft which can resultin arcing into the interior which can fry various circuits including those that control the satellite. Over the the years we have lost a number of Geosats this way.

Steve

[A-L-E-X]

Actually, Eta Carinae's last outburst was more of a mass loss event rather than a nova which is a mass transfer event resulting in a "modest" explosion. In that regard, novae are similar but much less intense than a Type Ia Supernova which results when a star transfers enough mass to a white dwarf companion (or two WD's merge) to push it over the Chandrasekhar limit at which point the entire white dwarf detonates. Eta Carinae is far more massive than the progenitor of the Crab Supernova which would have been a regular Type II event or core collapse of a star of 8-15 Solar masses-this is confirmed by the presence of the neutron star which is the collapsed core at about 1.6 Solar mass. Eta Carinae depending upon how much mass it loses before collapse could be a hypernova where the core immediately collapses into a Black Hole. In order for the GRB to be Earth Directed the magnetic axis of Eta would have to point towards us.

About the SAA, the main reason that Hubble does not take observations when transitting the South Atlantic Anomaly is that it is among a class of satellites that use magnetic torquers for attitude control and they don't work so well when the satellite is in the SAA. Another problem in the anomaly involves Van Allen dumping which occurs during the late decay phase of a Geomagnetic storm. When that occurs the normal flux of electrons with energies > 2 MeV at satellite altitudes increases sharply and stays high for a period of days (as it currently is now). The problem for a spacecraft in this situation unlike the one with high energy protons (bit flips or Single Event Upsets), is spacecraft charging where a strong electrical charge builds up on the surface of the spacecraft which can resultin arcing into the interior which can fry various circuits including those that control the satellite. Over the the years we have lost a number of Geosats this way.

Steve

The SAA seems to have adversely affected laptops aboard space shuttles that passed over it. Predictions estimate that by 2240 the SAA may cover approximately half of the southern hemisphere. Hopefully, our technology will be at least someone more advanced and resistant to its effects by then.

Steve, you know which stars I find most intriguing for future hypernova possibilities? S Doradus in the Large Magellanic Cloud, for one. Also the massive stars inside the Tarantula Nebula of the LMC like R136a. I know they're in satellite galaxies, but the sheer massiveness of these stars is almost beyond belief. Any ideas how these stars got to be so massive and we dont see anything like this in our own galaxy?

These are so bright that you should actually be able to see them with a small telescope, even though theyre in another galaxy! Of course, you'd have to be at very low latitudes.

I wish these were closer by and then we would have a real light show

http://en.wikipedia.org/wiki/S_Doradus

S Doradus is the brightest star in the Large Magellanic Cloud, a satellite of the Milky Way. A hypergiant, it is one of the most luminous stars known (sometimes more luminous than −10 absolute magnitude), but so far away that it is invisible to the naked eye.

This star belongs to its own eponymous S Doradus class of variable stars (these classes are usually named after their prototypes); also designated as the class luminous blue variable or LBV. S Doradus exhibits long, slow changes in brightness, punctuated by occasional outbursts.

http://en.wikipedia.org/wiki/R136a

R136, formally known as RMC 136, is a super star cluster[2] near the center of the 30 Doradus complex (also known as the Tarantula Nebula), in the Large Magellanic Cloud. It is a young star cluster, age 1-2 million years,[2] of giant and supergiant stars. The majority of its stars are of spectral type O3,[2] with 39 confirmed O3-type stars.[2][3] Additionally, there are several confirmed Wolf-Rayet stars.[3][4]

The cluster R136 contains several components.[1] The nature of the central component, R136a, was initially unclear. R136a was once thought to be a hypergiant star of about 1500 solar masses, 30 million times as bright as the sun, burning at 55-60,000K and about 50 million miles in diameter. R136a's true nature was resolved by holographic speckle interferometry and found to be a dense star cluster[5] containing, among other things, twelve very massive and luminous stars in its core.[6] These stars had initial masses calculated to be in the range of 37 to 76 solar masses.[6] Three extremely luminous stars (R136a1, R136a2 and R136a3) dominate the cluster and are separated by only 0.10 and 0.48 arcsec. One of the stars, R136a1, is the most massive star found to date with 265 solar masses,[7] as well as the most luminous at 10,000,000 times the brightness of the Sun.[8] R136 produces most of the energy that makes the Tarantula Nebula visible. The estimated mass of the cluster is 450,000 solar masses, suggesting it will probably become a globular cluster in the future.[9]

http://en.wikipedia.org/wiki/R136a1

R136a1 is a blue hypergiant star, currently on record as the most massive star known, at an estimated 265 solar masses.[2] The star also holds the record for the most luminous at 8,700,000 times the luminosity of the Sun.[2] It is a member of R136, a super star cluster near the center of the 30 Doradus complex (also known as the Tarantula Nebula), in the Large Magellanic Cloud. The mass of the star was determined by astronomers at the University of Sheffield.Contents [hide]

1 Discovery

2 Physical characteristics

3 See also

4 References

[edit]

Discovery

News of the star's discovery was published in July 2010. A team of British astronomers led by Paul Crowther, Professor of Astrophysics at the University of Sheffield, used European Southern Observatory's Very Large Telescope (VLT) in Chile, as well as data from the Hubble Space Telescope, to study two star clusters, NGC 3603 and R136a.[3] R136a was once thought to be a supermassive object with 1000–3000 solar masses. R136a's nature was resolved by holographic speckle interferometry and found to be a dense star cluster.[4] The team found several stars with surface temperatures exceeding 40,000 K, more than seven times that of the Sun, and which are several million times brighter. At least three of the stars weigh in at about 150 solar masses.

[edit]

Physical characteristics

Left to right: a red dwarf, the Sun, a blue dwarf, and R136a1. R136a1 is not the largest known star in terms of volume; this distinction belongs to VY Canis Majoris.

R136a1 is a Wolf-Rayet star with surface temperature over 50,000 K.[2] Like other stars that are close to the Eddington limit, R136a1 has been shedding a large fraction of its initial mass through a continuous stellar wind. It is estimated that, at its birth, the star held 320 solar masses and has lost 50 solar masses over the past million years.[2]

Stars between about 8 and 150 solar masses explode at the end of their lives as supernovae, leaving behind neutron stars or black holes. Having established the existence of stars between 150 and 300 solar masses, astronomers suspect that such an enormous star will perish as a hypernova, a stellar explosion with an energy of over 100 supernovae (1046 joules). The star may also die prematurely long before its core could collapse naturally from lack of fuel as a "pair instability supernova". Hydrogen-fusing cores should create large numbers of electron–positron pairs, which drop the thermal pressure present within the star to the point a partial collapse occurs. If R136a1 underwent such an explosion it would fail to leave behind a black hole and instead the dozen solar masses of iron within its core would be blown out into the interstellar medium as a supernova remnant.

[A-L-E-X]

Here's one in our own galaxy, less than 5,000 LY away.

Not as spectacular as the ones in the LMC though but it can easily be seen from the Northen Hemisphere with the naked eye. It's actually not too far from Sirius and near Orion.

http://en.wikipedia....Y_Canis_Majoris

VY Canis Majoris (VY CMa) is a red hypergiant star located in the constellation Canis Major. At between 1800 and 2100 solar radii (8.4–9.8 astronomical units, 2.7 billion km or 1.7 billion miles in diameter), it is currently the largest known star and also one of the most luminous known. It is located about 1.5 kiloparsecs (4,900 light years, 4.6×1016 km or 2.9×10

16 mi) away from Earth. Unlike most hypergiant stars, which occur in either binary or multiple star systems, VY CMa is a single star. It is categorized

as a semiregular variable and has an estimated period of 2000 days.[5]

.....

Life expectancy

The star has been discovered to be very unstable, having thrown off much of its mass into its surrounding nebula. Astronomers, with the help of the Hubble Space Telescope, have predicted that the VY Canis Majoris will be destroyed, as a supernova, in less than 100,000 years. [1]

BTW the same nebula that harbors Eta Carinae contains an even bigger star:

http://en.wikipedia.org/wiki/HD_93129A

HD 93129A is one of the most luminous stars in the Milky Way. This very young blue hypergiant is an O-type hypergiant located about 7500 light-years from Earth in the bright nebula NGC 3372, the same nebula that harbors other super luminous stars, like Eta Carinae.

HD 93129A is actually the brighter member of a binary system that, with its dimmer companion—also an O3 Ia supergiant (HD 93129B)—has an overall mass of 200 solar masses.

[Mencken_Fan]

I agree and the link between them and cyclic climate change is actually growing; some of the graphs on the first link are pretty telling. More research = more knowledge = more actual science (minus all the crappy politics).

I would suggest if you pull back the curtain you'll find most "crappy politics" is just religion in disguise.

American government (at every level) is awash with people who reject evolution. How can we expect any rational thought from them when it comes to any other scientific discussion? From gays, to abortion, to science itself; the battle is not liberal vs. conservative politics, it's rationalism vs. religion. To see it otherwise is self-deluding.

There are many rational conservatives; just as there are many irrational liberals. The uphill battle science faces is the same one today it has always faced; the battle with religion. Until religion loosens its grip on America, we will continue sliding ever downward on the global totem pole of science.

For me personally, each decade is more intellectually discouraging than the previous. I see America's 'intellectual infrastructure' a desert today...but fortunately it's still dotted with oases like this website.

[A-L-E-X]

I would suggest if you pull back the curtain you'll find most "crappy politics" is just religion in disguise.

American government (at every level) is awash with people who reject evolution. How can we expect any rational thought from them when it comes to any other scientific discussion? From gays, to abortion, to science itself; the battle is not liberal vs. conservative politics, it's rationalism vs. religion. To see it otherwise is self-deluding.

There are many rational conservatives; just as there are many irrational liberals. The uphill battle science faces is the same one today it has always faced; the battle with religion. Until religion loosens its grip on America, we will continue sliding ever downward on the global totem pole of science.

For me personally, each decade is more intellectually discouraging than the previous. I see America's 'intellectual infrastructure' a desert today...but fortunately it's still dotted with oases like this website.

I think youre on the right track with this-- I dont really blame either side of the aisle on this, as much as I blame the extremists on both sides-- and this goes for religion as well as politics. Subjectivity created this situation, only objectivity can provide the solution.

[aslkahuna]

There is still some debate as to whether or not R136a is a single star or not. As to what kind of show we could get from a LMC Supernova one only needs to look back to Supernova 1987A. This was a subluminous Type II (the progenitor was a Blue B class Supergiant like ß Orionis rather than the classic Red one and hence a smaller star) Supernova yet it peaked at slightly above 3rd Magnitude-not bad for being 160,000 ly away. Also note that S Andromedae a Supernova in M31 (2.4 million ly distant) was 5th magnitude. As far as galactic Supernova are concerned,the big problem here is interstellar dust. Since Kepler's Star in 1604 there have been at least 1 if not two galactic Supernova in the Milky Way both of which were dimmed by dust as to be invisible to the naked eye.

Steve

[A-L-E-X]

There is still some debate as to whether or not R136a is a single star or not. As to what kind of show we could get from a LMC Supernova one only needs to look back to Supernova 1987A. This was a subluminous Type II (the progenitor was a Blue B class Supergiant like ß Orionis rather than the classic Red one and hence a smaller star) Supernova yet it peaked at slightly above 3rd Magnitude-not bad for being 160,000 ly away. Also note that S Andromedae a Supernova in M31 (2.4 million ly distant) was 5th magnitude. As far as galactic Supernova are concerned,the big problem here is interstellar dust. Since Kepler's Star in 1604 there have been at least 1 if not two galactic Supernova in the Milky Way both of which were dimmed by dust as to be invisible to the naked eye.

Steve

S Andromeda was back in 1881 or something like that wasnt it, Steve? I wonder how much its absolute magnitude that one was-- I've heard it might have been a hypernova. Sounds like it was close to the brightness of the whole galaxy!

[A-L-E-X]

Found it-- I was close, it was 1885

Hubble found the remnants....

http://en.wikipedia.org/wiki/S_Andromedae

S Andromedae (also SN 1885A) was a supernova in the Andromeda Galaxy, the only one seen in that galaxy so far by astronomers, and the first ever noted outside the Milky Way. It is also known as "Supernova 1885".

It was discovered on August 19, 1885, by the Irish amateur astronomer Isaac Ward in Belfast,[1] and independently the following day by Ernst Hartwig at Dorpat (Tartu) Observatory in Estonia. It reached magnitude 6, but faded to magnitude 16 by February 1890.

The star was reported to be reddish in color and declined very rapidly in brightness, which is atypical for Type Ia supernovae. Unfortunately no spectroscopic data is available.

The location of the supernova event was 16″ from the relatively bright nucleus of the galaxy. This made detection of the supernova remnant difficult, and multiple attempts proved unsuccessful. Finally, in 1988, astronomer R. A. Fesen and others using the 4-meter Mayall telescope at Kitt Peak discovered the iron-rich remnant of the explosion.[2] Further observations were made with the Hubble Space Telescope in 1995.

[LakeEffectKing]

The SAA seems to have adversely affected laptops aboard space shuttles that passed over it. Predictions estimate that by 2240 the SAA may cover approximately half of the southern hemisphere. Hopefully, our technology will be at least someone more advanced and resistant to its effects by then.

Steve, you know which stars I find most intriguing for future hypernova possibilities? S Doradus in the Large Magellanic Cloud, for one. Also the massive stars inside the Tarantula Nebula of the LMC like R136a. I know they're in satellite galaxies, but the sheer massiveness of these stars is almost beyond belief. Any ideas how these stars got to be so massive and we dont see anything like this in our own galaxy?

These are so bright that you should actually be able to see them with a small telescope, even though theyre in another galaxy! Of course, you'd have to be at very low latitudes.

I wish these were closer by and then we would have a real light show

http://en.wikipedia.org/wiki/S_Doradus

S Doradus is the brightest star in the Large Magellanic Cloud, a satellite of the Milky Way. A hypergiant, it is one of the most luminous stars known (sometimes more luminous than −10 absolute magnitude), but so far away that it is invisible to the naked eye.

This star belongs to its own eponymous S Doradus class of variable stars (these classes are usually named after their prototypes); also designated as the class luminous blue variable or LBV. S Doradus exhibits long, slow changes in brightness, punctuated by occasional outbursts.

http://en.wikipedia.org/wiki/R136a

R136, formally known as RMC 136, is a super star cluster[2] near the center of the 30 Doradus complex (also known as the Tarantula Nebula), in the Large Magellanic Cloud. It is a young star cluster, age 1-2 million years,[2] of giant and supergiant stars. The majority of its stars are of spectral type O3,[2] with 39 confirmed O3-type stars.[2][3] Additionally, there are several confirmed Wolf-Rayet stars.[3][4]

The cluster R136 contains several components.[1] The nature of the central component, R136a, was initially unclear. R136a was once thought to be a hypergiant star of about 1500 solar masses, 30 million times as bright as the sun, burning at 55-60,000K and about 50 million miles in diameter. R136a's true nature was resolved by holographic speckle interferometry and found to be a dense star cluster[5] containing, among other things, twelve very massive and luminous stars in its core.[6] These stars had initial masses calculated to be in the range of 37 to 76 solar masses.[6] Three extremely luminous stars (R136a1, R136a2 and R136a3) dominate the cluster and are separated by only 0.10 and 0.48 arcsec. One of the stars, R136a1, is the most massive star found to date with 265 solar masses,[7] as well as the most luminous at 10,000,000 times the brightness of the Sun.[8] R136 produces most of the energy that makes the Tarantula Nebula visible. The estimated mass of the cluster is 450,000 solar masses, suggesting it will probably become a globular cluster in the future.[9]

http://en.wikipedia.org/wiki/R136a1

R136a1 is a blue hypergiant star, currently on record as the most massive star known, at an estimated 265 solar masses.[2] The star also holds the record for the most luminous at 8,700,000 times the luminosity of the Sun.[2] It is a member of R136, a super star cluster near the center of the 30 Doradus complex (also known as the Tarantula Nebula), in the Large Magellanic Cloud. The mass of the star was determined by astronomers at the University of Sheffield.Contents [hide]

1 Discovery

2 Physical characteristics

3 See also

4 References

[edit]

Discovery

News of the star's discovery was published in July 2010. A team of British astronomers led by Paul Crowther, Professor of Astrophysics at the University of Sheffield, used European Southern Observatory's Very Large Telescope (VLT) in Chile, as well as data from the Hubble Space Telescope, to study two star clusters, NGC 3603 and R136a.[3] R136a was once thought to be a supermassive object with 1000–3000 solar masses. R136a's nature was resolved by holographic speckle interferometry and found to be a dense star cluster.[4] The team found several stars with surface temperatures exceeding 40,000 K, more than seven times that of the Sun, and which are several million times brighter. At least three of the stars weigh in at about 150 solar masses.

[edit]

Physical characteristics

Left to right: a red dwarf, the Sun, a blue dwarf, and R136a1. R136a1 is not the largest known star in terms of volume; this distinction belongs to VY Canis Majoris.

R136a1 is a Wolf-Rayet star with surface temperature over 50,000 K.[2] Like other stars that are close to the Eddington limit, R136a1 has been shedding a large fraction of its initial mass through a continuous stellar wind. It is estimated that, at its birth, the star held 320 solar masses and has lost 50 solar masses over the past million years.[2]

Stars between about 8 and 150 solar masses explode at the end of their lives as supernovae, leaving behind neutron stars or black holes. Having established the existence of stars between 150 and 300 solar masses, astronomers suspect that such an enormous star will perish as a hypernova, a stellar explosion with an energy of over 100 supernovae (1046 joules). The star may also die prematurely long before its core could collapse naturally from lack of fuel as a "pair instability supernova". Hydrogen-fusing cores should create large numbers of electron–positron pairs, which drop the thermal pressure present within the star to the point a partial collapse occurs. If R136a1 underwent such an explosion it would fail to leave behind a black hole and instead the dozen solar masses of iron within its core would be blown out into the interstellar medium as a supernova remnant.

265 solar masses (relatively speaking) doesn't seem like it would be the most massive star discovered (for R136a1)....is that a misprint?? I saw this video and would think it would be ALOT more......

[A-L-E-X]

265 solar masses (relatively speaking) doesn't seem like it would be the most massive star discovered (for R136a1)....is that a misprint?? I saw this video and would think it would be ALOT more......

LEK, I dont think its a misprint because usually the largest stars in terms of diameter are actually not very dense, so their mass gets spread out over a large area. The same is the case with planets; if you put Saturn in a large bath tub, it would float!

265 solar masses is huge because theory previously limited the largest stars to about 100 solar masses, but now we've found a few "hypergiants" that are much more massive. It can be confusing though because a distinction must be made in terms of size (diameter) and mass.

[A-L-E-X]

VY Canis Majoris is likely less massive than R136a because its a red hypergiant, which is an older star (like Betelgeuse is.) R136a is a member of a rare class of stars called Wolf Rayet and its actually bluish-violet, much hotter, more luminous and much younger (blue-- higher frequency than red.) But these stars burn through their fuel quickly, so their lifetimes are limited to about 10 million years or so. And like the article says, it was probably much more massive than this 1 million years ago-- they shed mass at a dizzying pace.

[LakeEffectKing]

LEK, I dont think its a misprint because usually the largest stars in terms of diameter are actually not very dense, so their mass gets spread out over a large area. The same is the case with planets; if you put Saturn in a large bath tub, it would float!

265 solar masses is huge because theory previously limited the largest stars to about 100 solar masses, but now we've found a few "hypergiants" that are much more massive. It can be confusing though because a distinction must be made in terms of size (diameter) and mass.

Yeah, I just went and looked it up.....Just incredible how the gigantic stars can be so much less dense...must be incredible variability with in the tug of war between gravity and radiative pressures....

[A-L-E-X]

Ok, I just looked up the numbers....

R136A

Details

Mass 265+80

−35[2] M☉

Radius 35.4+4.0

−3.6[2] R☉

Luminosity ≈ (8.7)×106[2] L☉

Temperature 53,000 ± 3,000[2] K

VY Canis Majoris

Details

Mass ~30[7]-40[8] M☉

Radius ~1800-2,100[9] R☉

Luminosity ~450,000[10][11] L☉

Temperature ~3000[11] K

Note the differences in temp, radius and mass. The only thing VY CMa has R136a beat in is radius-- in everything else R136a is greater.

[A-L-E-X]

Yeah, I just went and looked it up.....Just incredible how the gigantic stars can be so much less dense...must be incredible variability with in the tug of war between gravity and radiative pressures....

It is and Betelgeuse is one of those red supergiants, sort of like a lesser version of that star in the video. But its much closer and actually the first star to be seen as a disc rather than just a point of light. We've even been able to see "starspots" on it!

[LakeEffectKing]

It is and Betelgeuse is one of those red supergiants, sort of like a lesser version of that star in the video. But its much closer and actually the first star to be seen as a disc rather than just a point of light. We've even been able to see "starspots" on it!

Fascinating stuff! Everytime I contemplate the extreme boundaries of our knowledge of the Universe (and beyond...) and the happenings around extreme gravity (SMBH's), I often wonder if science and religion don't end up with the same endpoint from an "all knowing" aspect. Just a whole lot of difference in how we would get to the endpoint!

[A-L-E-X]

Fascinating stuff! Everytime I contemplate the extreme boundaries of our knowledge of the Universe (and beyond...) and the happenings around extreme gravity (SMBH's), I often wonder if science and religion don't end up with the same endpoint from an "all knowing" aspect. Just a whole lot of difference in how we would get to the endpoint!

I think of that also, the difference is religion incorporates mankind's subjectivity and science seeks to be objective. Although, there are big egos in science also, that are resistant to new ideas, but eventually they succumb and progress marches on.

[aslkahuna]

Wolf-Rayet Stars are the progenitors of Type Ib Supernovae with Gamma2 Velorum being the closest one to us. If a remnant of S Andromedae has been found that means that it was not a Type Ia because those leave no remnant cores since they result from the complete detonation of a White Dwarf rather than a core collapse. The typical absolute magnitude of a Supernova is around -20 to -19. M31 has an absolute magnitude of around -22 and is magnitude 4.5 in our sky. I have seen a few extragalactic Supernovae and yes they are as bright or brighter than the host Galaxy.

Steve