Stars crossing paths with sun caused Dino's demise

[rlb2]

Are we finally coming to terms with our planets fate? If we know what’s coming at us in the future then we can plan to do something about it.<br /><br /><font color="orange">A star named Gliese 710, found by Hipparcos and reported in 1999, will pass within 1 light-year of the Sun. That puts it some 70,000 times the distance from Earth to the Sun, on the very fringes of our solar system where icy objects are thought to roam in what's known as the Oort Cloud. Such stellar close calls in the past are thought to have rerouted comets from the Oort Cloud toward the inner solar system, where some hit Earth.<font color="white"><br /><br />http://www.space.com/scienceastronomy/rebel_stars_041026.html<br /><br />What about dark matter or cold dead stars that dont emit much radiation?</font></font> <div class="Discussion_UserSignature"> Ron Bennett </div>

 

[rogers_buck]

http://www.solstation.com/stars2/gl710.htm

 

[rlb2]

Thanks - this sounds like it may have been discussed many times before about the collision effect of comets but think of the other possibilities.. <br /><br />We will know when and where it will cross our path and it will be relatively close to Earth within 1.1 light years when it crosses. A very slight change in trajectory could cause a problem for us if it happened within the next thousand years. We can observe it on its approach and see if it would be worth sending voyagers out to meet it to colonize any planets it has. If humans survive the next million years then it would be an economical way to spread the human seeds to other places in our galaxies. <br /><br />Who knows in a million years we may have the technology to take a planet size ort cloud object and relocate it close enough to the new sun to colonize it, if there isn't a habitable planet surrounding it and if we can find a planet-size object in the Ortt cloud.<br /><br />It’s a wondering star so it will flyby other stars on its journey into the unknown, spreading the earthly parasites called - Human Beings.<br /> <div class="Discussion_UserSignature"> Ron Bennett </div>

 

[silylene old]

I wonder how bright Gliese 710 would be in the Earth's sky at that time?<br /><br />Depending upon its orbital location at the time of close passage, a person standing on Sedna might get a better view of Gliese 710. I wonder what the relative magnitudes of the sun and Gliese 710 might be? <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center"><em><font color="#0000ff">- - - - - - - - - - - - - - - - - - - - - -</font></em> </div><div class="Discussion_UserSignature" align="center"><font color="#0000ff"><em>I really, really, really miss the "first unread post" function.</em></font> </div> </div>

 

[thechemist]

Hi there silylene.<br /><br />According to rogers_buck's link : <font color="yellow">"At its closest approach, Gl 710 will rival the brightness of the red supergiant Antares, although it is currently not even visible to the naked eye of Earth-bound Humans "</font><br /><br />Antares is the 15th brightest star in the sky. Not that bright ...<br /><br />I wonder if they have done reverse calculations to see if any of the stars now moving away from the Sun have passed close by during earth's history.<br /><br />Cheers ! <br /><br />Edited to correct buck's name. <div class="Discussion_UserSignature"> <em>I feel better than James Brown.</em> </div>

 

[nexium]

My guess is the media is disbursing the usual errors. Most stars (even five solar mass compact stars) at a distance of one light year would not cause mass extinctions on Earth. A pass at 1% of a light year = 60 billion miles = 100,000,000,000 kilometers would change the orbit of Earth, such that we should notice a climate change 65 billion years ago. The sun would be about 440,000 times brighter than a G2 visitor at a distance of 60 billion miles.<br /> A pass at one millionth of a light year = 6,000,000 miles would likely eject Earth from the solar system. A G2 star would be 225 times brighter than the sun, which would likely sterilize most of Earth. A dim red, class m star likely would not seriously over-heat Earth briefly at 6 million miles and there is a very slight chance we would like the new orbit of Earth. Neil

 

[nexium]

I agree with crazyeddie except, thousands of comets instead of millions, But it only takes one big one to cause mass extintion.<br /> If the incoming comet approaches our sun at 5000 (average) miles per hour the first 200,000 hours, it moves inward one billion miles, so there is a very long delay between perturbed and impact. 200,000 hours is 8333 days = 22 years. Most of the Oort cloud is many billions of miles from the sun. Neil

 

[rlb2]

<font color="orange">I wonder what the relative magnitudes of the sun and Gliese 710 might be?<font color="white"> <br /><br /><br />Would be looking at a new bright star if you compare it with the luminosity of its present state. Gliese 710 brightness over time will change faster than our suns. The Chemist did a good job of answering that but will it be as bright or brighter in 1.4 million years as it is today?<br /><br /><br />Its currently 64 light years away from Earth. It must be traveling real fast relative to our sun to make up that distance in only 1.4 million years.<br /><br />The last time I checked, which was a few years ago, (Carl Sagen example) our sun was traveling over 300,000 KPH through the spiral arm of our galaxy. Our Galaxy was traveling somewhere in the order of over 500,000 KPH through its section of the universe.<br /></font></font> <div class="Discussion_UserSignature"> Ron Bennett </div>

 

[rlb2]

<font color="orange">Yeah, maybe about 1.4 MY from now. I'm not worried. <font color="white"><br /><br />Me neither, a small course correction within the next 1000 years could make a difference. That course correction by the gravitational tug of an unseen massive object or a collision with a large object could do the trick. It still will be very remote to point it in the same direction of our sun. <br /><br />At any rate our great grandchildren on the order of 25,000th generations if you take the average age of life expectancy to be 58 years old, may be very concerned.</font></font> <div class="Discussion_UserSignature"> Ron Bennett </div>

 

[Maddad]

silylene<br />"<font color="Yellow">I wonder how bright Gliese 710 would be in the Earth's sky at that time?</font>"<br /><br />Pretty durn bright: "<font color="Lime">The faint 9th magnitude red dwarf, currently 63 light-years away in the constellation Ophiucus, was recently discovered to be approaching our Solar System. Known in catalogs of nearby stars as Gliese (Gl) 710 it is predicted to come within nearly 1 light-year of the Sun ... about 1.5 million years from now. At that distance this star, presently much too faint to be seen by the naked eye, will blaze at 0.6 magnitude - rivaling the apparent brightness of the mighty red giant Antares.</font>"<br /><br />Astronomy Picture of the Day for 2001 July 7 <br />http://antwrp.gsfc.nasa.gov/apod/ap010707.html

 

[Maddad]

nexium<br />"<font color="Yellow">My guess is the media is disbursing the usual errors. Most stars (even five solar mass compact stars) at a distance of one light year would not cause mass extinctions on Earth.</font>"<br /><br />The problem is not so much the star itself, but the Oort Cloud objects that it disturbs. We think they extend to about two light-years, which means that the Oort Cloud systems of both stars will comingle as they pass. Many of the objects from both stars will fall sunward.<br /><br />We have counted 50,000 of them the size of Hawaii, 200 miles across, in our own Oort Cloud. Since the number of them goes up by the inverse square of their size, there should be twenty million of them as large as the Chicxulub object that brought about the KT extinction of the dinosaurs. That object was a measly 10 miles across.

 

[nexium]

Hi maddad: Is 50,000 (200 miles across) in our own Oort cloud a firm number, or an estimate? I had thought perhaps 20 in the Kupier belt and zero confirmed in the Oort cloud. How do we estimate the dimentions of a 30th magnetude point of light?<br /> They would not be all the same size, so average 250 miles = about 10 million cubic miles average volumn = 500,000 million = 1/2 trillion cubic miles for the 50,000 over 200 miles. I'm hazzy on how to work inverse square backwards, but does this not give more than one Earth mass total, if we assume inverse square holds down to one millimeter across?<br /> Using your 20 million over 10 miles across/ average 25 miles = about 10,000 cubic miles each = 200,000 million cubic miles total volume. The volume of Earth is about 260,000 million cubic miles. Please check my arithmetic and logic. Neil