Origins of Life on Earth (and Maybe Elsewhere) Created in a Lab
Climate-Change Skeptics Proved Wrong (Again): Sun Nixed As Cause

Is There a Milky-Way Galaxy/Earth Biodiversity Link? Experts Say "Yes"

Phot10b04normal_21n 1999, Astronomers focusing on a star at the center of the Milky Way, measured precisely how long it takes the sun to complete one orbit (a galactic year) of our home galaxy: 226 million years.

The last time the sun was at that exact spot of its galactic orbit, dinosaurs ruled the world. The Solar System is thought to have completed about 20–25 orbits during its lifetime or 0.0008 orbit since the origin of humans.

Using a radio telescope system that measures celestial distances 500 times more accurately than the Hubble Space Telescope, astronomers plotted the motion of the Milky Way and found that the sun and its family of planets were orbiting the galaxy at about 135 miles per second. That means it takes the solar system about 226 million years to orbit the Milky Way and puts the most precise value ever determined on one of the fundamental motions of the Earth and its sun.

The sun circles the Milky Way at a speed of about 486,000 miles per hour. And every object in the universe is moving apart from the other objects as the universe expands at a constantly accelerating rate.

The sun is one of about 100 billion stars in the Milky Way, one of billions of ordinary galaxies in the universe. The Milky Way is a spiral galaxy, with curving arms of stars pinwheeling out from a center.The solar system is about halfway out on one of these arms and is about 26,000 light years from the center. A light year is about 6 trillion miles.

For their solar system measurement, the astronomers focused on Sagittarius A, a star discovered over two decades ago to mark the Milky Way's center. Over a 10-day period, they measured the apparent shift in position of the star against the background of stars far beyond. The apparent motion of Sagittarius A is very, very small, just one-600,000th of what could be detected with the human eye, the astronomers said.

The measurement adds supports to the idea that the Milky Way's center contains a supermassive black hole- an object, much smaller than our own solar system, contains a black hole about 2.6 million times more massive than the sun.

Earlier this year, a team of researchers at the University of Kansas came up with an out-of-this-world explanation for the phenomenon of mass extinctions on Earth that hinges upon the fact that stars move through space and sometimes rush headlong through galaxies, or approach closely enough to cause a brief cosmic tryst.

Researchers at the University of California, Berkeley found that marine fossil records show that biodiversity increases and decreases based on a 62-million-year cycle. At least two of the Earth's great mass extinctions-the Permian extinction 250 million years ago and the Ordovician extinction about 450 million years ago-correspond with peaks of this cycle, which can't be explained by evolutionary theory.

Our own star moves toward and away from the Milky Way's center, and also up and down through the galactic plane. One complete up-and-down cycle takes 64 million years- suspiciously close to the Earth's biodiversity cycle.

Once the researchers independently confirmed the biodiversity cycle, they then proposed a novel mechanism whereby which the Sun's galactic travels is causing it.

It’s no secret that the Milky Way is being gravitationally pulled toward a massive cluster of galaxies, called the Virgo Cluster, which is located about 50 million light years away. Adrian Melott and his colleague Mikhail Medvedev, speculate that as the Milky Way rushes towards the Virgo Cluster, it generates a so-called bow shock in front of it that is similar to the shock wave created by a supersonic jet.

"Our solar system has a shock wave around it, and it produces a good quantity of the cosmic rays that hit the Earth. Why shouldn't the galaxy have a shock wave, too?" Melott asks.

The galactic bow shock is only present on the north side of the Milky Way's galactic plane, because that is the side facing the Virgo Cluster as it moves through space, and it would cause superheated gas and cosmic rays to stream behind it, the researchers say. Normally, our galaxy's magnetic field shields our solar system from this "galactic wind." But every 64 million years, the solar system's cyclical travels take it above the galactic plane.

"When we emerge out of the disk, we have less protection, so we become exposed to many more cosmic rays," Melott has said.

The boost in cosmic-ray exposure may have a direct effect on Earth's organisms, according to paleontologist Bruce Lieberman. The radiation would lead to higher rates of genetic mutations in organisms or interfere with their ability to repair DNA damage. In this way, the process could lead to new species while killing off others.

Cosmic rays are also associated with increased cloud cover, which could cool the planet by blocking out more of the Sun's rays. They also interact with molecules in the atmosphere to create nitrogen oxide, a gas that eats away at our planet's ozone layer, which protects us from the Sun's harmful ultraviolet rays.

Richard Muller, one of the UC Berkeley physicists who co-discovered the cycle, said Melott and his colleagues have come up with a plausible galactic explanation for the biodiversity cycle.

If future studies confirm the galaxy-biodiversity link, it would force scientists to broaden their ideas about what can influence life on Earth. "Maybe it's not just the climate and the tectonic events on Earth," Lieberman said. "Maybe we have to start thinking more about the extraterrestrial environment as well."

Posted by Casey Kazan.

Editor's Note:

National Geographic's new book, Hubble: Imaging Space and Time reveals the full story of the remarkable telescope. Also coincident with the 400th anniversary of Galileo’s first telescope, this gorgeous, large format, full-color volume contains an unprecedented collection of powerful, cutting-edge photographs gathered by Hubble over its nearly 20-year lifetime of putting a face on space.

Related Galaxy posts:

GAIA -Mapping the Family Tree of the Milky Way
The "Hubble Effect" -A Galaxy Insight

Story Links:

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I aggree on the biodiversity link. Of cause life on Earth is affected by the galactic emissions of all kinds of cosmic rays.
But I´m not sure about the 226 mio. years of orbit because of my alternative view of what´s really going on in our galaxy.
In my opinion, there is an outgoing movement from the center and not any attraction from a "black hole".
The "hole" represents just a cosmic swirl - like in Hurricanes - and the bars is an evidence for a suddenly outburst from an explosion, spewing large spheres of gas and matter outwards in the galatic arms.
That is: We have a fast rotating galaxy center which is pushing gas and matter outwards which later on becomes Stars and Planets that orbits comparatively slower and slower around the galaxy center as the gas/stars and matter/planets moves further and further away from the galaxy center.
If so, the Solar System orbit will increase the orbit time more and more.
And if so: This expansive movement of our Solar System in our galaxy, could very well be a cause for an illusive/optical statement of "the expanding Univers".

Natural Philospoher Ivar Nielsen -

so...when is the next extinction according to this?

"And if so: This expansive movement of our Solar System in our galaxy, could very well be a cause for an illusive/optical statement of "the expanding Univers"."

I thought scientists believe the gravitational forces within a galaxy cancel out the expanding effects of the greater universe. And that therefore there isn't an "expansive movement of our solar system"

Pretty cool stuff dude! Wow!


Since everything is moving at incredible speeds could we master interstellar space travel by especially stopping a craft stationary and let everything move away at 486,000mph or something similar?

"Since everything is moving at incredible speeds could we master interstellar space travel by especially stopping a craft stationary and let everything move away at 486,000mph or something similar?"

No. Momentum.

When you are sitting in a plane and you are at stable cruising altitude, do you find yourself being flung to the back of the plane whenever you get out of your seat? No, because you are actually moving at the speed the plane is.

And you can't just stop yourself from going at that speed.

You are also committing the genetic fallacy of reasoning. Just because something has had a different cause in the past does not preclude it from having a different cause now.

Sagittarius Dwarf Elliptical Galaxy, get ready for Planet Earth! We soon rejoin our space brothers!

Sagittarius Dwarf Elliptical Galaxy, get ready for Planet Earth! We soon rejoin our space brothers!!!

Great stuff. Seems like we are finally putting the pieces together.

Great stuff. Seems like we are finally fitting the pieces together.

Interesting theory, however do not forget that hurricanes from on the earth due to (in part) rotations of our planet interacting with wind flows. If the pattern you describe is correct, then hurricane would have bars to in a since (wind patter wise at least).

The problem that the bars in the center of many spiral galaxies pose is that they are often not (if ever) on the axis of rotation. If matter where spewing out of the center, it would likely be coming out of the "poles" of the black hole shooting debris almost perpendicular to our axis of rotation (see active galaxies, quasars etc). The bars defy this in such a way that we do not presently have a proper understanding for this phenomenon.

Furthermore, what you propose about our orbit of rotation would reveal a serious flaw in laws of motion. I cannot say for sure how stable our orbit is around the Milky way but in observing our own planets movement around the sun shows that it would have to be fairly stable indeed not in the 5 billion years our system has been around we would have been ejected (or near the edge).

Indeed we have much to learn about our universe yet still as many if not most of what we observe is still unexplainable.

Present understanding is that expansion of the universe is not being canceled out by gravitational interactions (see dark energy). Recent evidence says that it has been accelerating however this is still up for debate.

So in others word after all these years Astrology is starting to be confirmed. How long before we realize nothing works independently, Our whole universe acts on its self and causes changes continuously. All that matters is the length of time your thinking in.

The black hole in the center of the galaxy is massive enough to keep the galaxy together. The correlation between the mass of the galactic central super-massive black hole and the rest of the galaxy has been proven - its the way things work for most galaxies.
The universe does not have a central mass to keep all the galaxies together, we are all basically orbiting each other as well as accelerating away from each other.

Yes, we are accelerating away from each other, that has been a fact since the Doppler effect was discovered (red shift/blue shift). The ultimate end-of-the-universe question is will we keep accelerating away, stagnate, or start accelerating towards each other at some point in time.

but, if we have another "accident", I don't think we'll have to worry about the end of the universe :)))

Ivar Nielson - You only need to attend a few lectures at a first year undergraduate astronomy module of the nearest institute that teaches physics to know that the evidence for a black hole at the centre of the galaxy is irrefutable. Sorry.

I've got this theory that theres a powered doughnut at the center of the galaxy. See, there was this bakery ...

Dear Lord! Anyone else remember the time when the daft knew they were full of it? Or at least had enough common sense to NOT spout off "theories" about things when they don't have even the most basic knowledge of the subject? Is there not one shred of embarassment anymore?

Anyway, I think the important part of this is, as someone above mentioned, when do we hit the North side again? They tie the extinction 250 million years ago to this and 62 * 4 = 248. Sooo ... we're either just heading into it or out of it depending on rounding.

In Carl Calleman's new book 'Purposeful Universe' he explains the relationship between the universe, galaxies, solar systems, planets, atoms and life, providing a unifying theory of how it all fits together.

Great stuff. Seems like we are finally putting the pieces together

Well guys, not sure about much of anything anymore... just know that our government, for the last 10 years has building super massive underground installations in preparation for alleged 2012 events. And... the Myans astrophysical calculations, after 1500+ years, are only off some 33 seconds... well you do the math. All you have to do is follow the money...
My guess is our planet is in for something truly ominous... I just wish we all knew the truth so we could prepare as a race. But, with overpopulation, limited resources, and human nature being what it is...only about 100 million or so will survive. And yes... it will be government, elites, and the super smart needed to rebuild society.

No,it's all wrong as usual. Giant bugs did it.

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