What if hypervelocity star came near Sun?

paulaireilly wrote:
Sorcerer wrote:
| How dangerous
| it could be for life on Earth?


Depends on the star and how close it passes.


I wonder what effect a direct collision between a sun sized star and
the Sun would have on life on Earth?

Haha!

Double-A

"Double-A" writes:

paulaireilly wrote:
Sorcerer wrote:
| How dangerous
| it could be for life on Earth?

Depends on the star and how close it passes.

I wonder what effect a direct collision between a sun sized star and
the Sun would have on life on Earth?

Haha!

Double-A

We'd know about it eight and a half minutes later...and shortly after that, we
wouldn't be around to wonder about it.

--
Patrick "The Chief Instigator" Humphrey ) Houston, Texas
chiefinstigator.us.tt/aeros.php (TCI's 2006-07 Houston Aeros)
LAST GAME: San Antonio 4, Houston 2 (November 21)
NEXT GAME: Friday, November 24 vs. San Antonio, 7:35

In the newsgroups:
alt.astronomy,
rec.arts.sf.science,
sci.astro,
sci.space.policy and
soc.history.what-if,
On 23 Nov 2006 19:40:59 -0600, The Chief Instigator
wrote:

"Double-A" writes:

paulaireilly wrote:
Sorcerer wrote:
| How dangerous
| it could be for life on Earth?

Depends on the star and how close it passes.

I wonder what effect a direct collision between a sun sized star and
the Sun would have on life on Earth?

Haha!

Double-A

We'd know about it eight and a half minutes later...and shortly after that, we
wouldn't be around to wonder about it.

That's when we would see it happen. If the hypervelocity star were
going at 99 percent of lightspeed, that's also about the time we'd
find out about it.
But the fastest speed in the original post is "4000 kilometres
per second", slow enough for astronomers to notice it by the time it
becomes the brightest star in the night sky, and have perhaps a few
weeks or months to contemplate the fact that it's heading straight
into the middle of the Solar System. And this isn't like an
Earth-grazing asteroid, where it's feasible to send a rocket up to
nudge it off of a collision course. At that speed it would push the
the Sun right out of the Solar System, with whatever's left of the two
stars moving out from the Sun's (former) position at an average of
2,000 km/s (if I calculate correctly, that's 1 AU every 8 days).
But presuming the immense solar flares (surely orders of magnitude
above anything we've seen) don't kill everyone (perhaps there's a
chance in mineshafts, if earthquakes aren't triggered by all this),
and the other star doesn't push the Sun or some parts of it into or
too near Earth, within a few weeks our new Sun(s) will be dimming as
it goes away, and the Earth goes on a straight path at its former
orbital speed of 13 miles per second. For anyone who's still alive,
it'll be a long, cold ride.

But even a star passing the Solar System "in interstellar space"
may have a negative effect on the Oort Cloud, as Frank Glover said.

From Wikipedia:
"The Oort cloud, alternatively termed the Öpik-Oort Cloud, is a
postulated spherical cloud of comets situated about 50,000 to 100,000
AU from the Sun. This is approximately 2000 times the distance from
the Sun to Pluto or roughly one light year, almost a quarter of the
distance from the Sun to Proxima Centauri, the star nearest the Sun."

So a star passing one light-year away is going to graze the Oort
Cloud and surely send lots of stuff in toward the Sun (and Earth),
though it may take centuries before we notice the comet traffic
increasing. But we'd know to expect it, because we would have seen the
star going by and know how close it was.

The closer the star's path to the Solar System, the more
devastating its effects, and the sooner those effects will happen.

"Double-A" wrote in message ups.com...
|
| paulaireilly wrote:
| Sorcerer wrote:
| | How dangerous
| | it could be for life on Earth?
|
|
| Depends on the star and how close it passes.
|
|
| I wonder what effect a direct collision between a sun sized star and
| the Sun would have on life on Earth?
|
| Haha!
|
| Double-A


He's a ****in' liar, I never wrote that. It is very bad form to attribute
questions others have asked to me, the snipping *******.

To answer your question, the effect prior to the event would be:

1) intelligent life on Earth would recognise the impending cause
of a supernova.
2) quasi-intelligent life would argue with futility, as per usual.


After the event, the effect would be:
insert personal definition of oblivion, zero for eternity, god, heaven, hell...

Androcles

Matt Giwer wrote:
....
Lets cut it as this point and look at the requirements for an
effect. First passing through a solar system is very low probability.
Second it has to pass close enough to a planet to impart enough momentum
to do something significant. Those odds are also very low. Very
significant is very very low.

But as to what would happen you need a serious program to deal with
orbital mechanics of the planets and then fly a few thousand through the
solar system and get a feel for the results.

Some simple consideration, on average "half" the planets are going
to be on the wrong side of the sun to be seriously affected. The closer
to the sun the less affected. Being tossed out of the solar system is
much more likely than falling into the sun but equally likely with a
highly elliptic orbit.

There is really not good answer other than learn the orbital
mechanics and think it through for yourself. There is no way to give a
decent answer without the listener knowing the subject.

Without breaking out the physics text to confirm ...

The momentum transfer (given planet v star the change in velocity, delta v is
good enough) would be 100% if the planet were to travel through the center of
the star and survive. That would add the speed of the star to the prior speed of
the planet.

As gravity is the coupling mechanism the percentage delta v would decrease as
with gravity, with the inverse of the distance.

Without calculation it should be maybe 0.1% at a million miles distance. A
million mile is a close encounter in this solar system. With 4000 km/s, 4 km/s
delta v compared to earth's 30 km/s orbital velocity is significant. However if
it were to cross Earth's orbit the odds are 2 in 2 x 92,000,000 x pi of coming
that close. The odds decreasing for planets further out. (2 x pi x radius and a
million miles on either side for the "2 in" odds.)

That only applies to actually coming near the orbit of the earth in the plane
of the ecliptic. There are 2 x 92,000,000 to 1 odds that it will pass above or
below the plane so for one passing within 92 million miles of the sun the
combined odds against are pi x 2 x 92,000,000 x 92,000,000 the earth being in
the wrong place at the wrong time.

When it comes to the Oort cloud that is thought to have millions of objects but
the density is so low that the odds should get even lower.

Additionally perturbing an Oort object as a random chance of sending it in any
direction. Futher it is so damned big it is likely going to be found stars we
see share and regularly exchange objects. In other words it is so big that
perturbing an object could send it into an extremely elliptical orbit around the
sun that still remains outside the orbit of Pluto. That a particular
perturbation would lose enough velocity to have a ellipticity that comes near
earth orbit is on the order of an act of god.

The article is talking about the events near the core of the galaxy where the
stellar density has an average separation of a few dozen AU.

If I can think of any other way to give a feel for it without learning the math
I'll post it.

--
The threat of force is always greater than using force. Fear is always
greater force than reality.
-- The Iron Webmaster, 3714
nizkor http://www.giwersworld.org/nizkook/nizkook.phtml
commentary http://www.giwersworld.org/opinion/running.phtml a5

Sorcerer wrote:
"Double-A" wrote in message ups.com...
|
| paulaireilly wrote:
| Sorcerer wrote:
| | How dangerous
| | it could be for life on Earth?
|
|
| Depends on the star and how close it passes.
|
|
| I wonder what effect a direct collision between a sun sized star and
| the Sun would have on life on Earth?
|
| Haha!
|
| Double-A


He's a ****in' liar, I never wrote that.


I see. Sorry about that.


It is very bad form to attribute
questions others have asked to me, the snipping *******.

To answer your question, the effect prior to the event would be:

1) intelligent life on Earth would recognise the impending cause
of a supernova.
2) quasi-intelligent life would argue with futility, as per usual.


Do you think there would be a lot of "repentiing", atheists attending
church sevices, etc.?



After the event, the effect would be:
insert personal definition of oblivion, zero for eternity, god, heaven, hell...

Androcles


Do you suppose the event could generate a powerful enough burst of
radiation to penetrate the Earth itself and kill those even on the
night side, or would those people have a few more hours to live? Or
could the shock wave blow away the entire Earth's atmosphere like down
off a thistle?

Double-A

"Double-A" wrote in message ups.com...
|
| Sorcerer wrote:
| "Double-A" wrote in message ups.com...
| |
| | paulaireilly wrote:
| | Sorcerer wrote:
| | | How dangerous
| | | it could be for life on Earth?
| |
| |
| | Depends on the star and how close it passes.
| |
| |
| | I wonder what effect a direct collision between a sun sized star and
| | the Sun would have on life on Earth?
| |
| | Haha!
| |
| | Double-A
|
|
| He's a ****in' liar, I never wrote that.
|
|
| I see. Sorry about that.

No need for apology, it's not your fault.

I answered the original post thusly:

"tracy" wrote in message oups.com...
| According to this article, the mysterious super-high speed stars are
| more numerous and fastest than previously though. What if one of these
| "hypervelocity" stars came through Sun's neighborhood?

In hypothetical sentences introduced by 'if' and referring to
past time, where conditions are to be deemed 'unfulfilled',
the verb will regularly be found in the pluperfect subjunctive,
in both protasis and apodosis.
-- Donet, "Principles of Elementary Latin Syntax"



| How dangerous
| it could be for life on Earth?

About the same as a bacterium in a crematorium. It might even be fatal.


|
| What would be safe distance a star moving at about 700 - 1000 km/s
| could get near Sun without disrupting the planetary system?

The speed is irrelevant, presence is.
You don't seem to grasp the scale of the Universe or even the scale
of the Solar System.
Suppose you have a cluster of 4 pixels (dots) in the middle of your
monitor screen to represent the sun, like this:

---- o ---- (Sun, drawn too big)

Then
|
|
|
| -- . ---- (Mercury)
|
|
|
|
| -- . -- (Venus)
|
|
|
|
| -- ' -- (Earth and Moon)


Jupiter (still a dot -- . --- ) is about where your ceiling is.
Saturn is then in your kitchen, the NEAREST star is at the end of the street,
and the imaginary black hole at the galactic centre is in the next city.
You have a far better chance of winning the lottery than meeting another
star up close and personal.
Androcles



|
|
| It is very bad form to attribute
| questions others have asked to me, the snipping *******.
|
| To answer your question, the effect prior to the event would be:
|
| 1) intelligent life on Earth would recognise the impending cause
| of a supernova.
| 2) quasi-intelligent life would argue with futility, as per usual.
|
|
| Do you think there would be a lot of "repentiing", atheists attending
| church sevices, etc.?


My opinion of faith is of no relevance, I do not attend christian churches,
moslem mosques, jewish synagogues or buddhist temples except to
examine and sometimes admire architecture.
I discuss physics and astronomy, dealing in fact.


|
|
|
| After the event, the effect would be:
| insert personal definition of oblivion, zero for eternity, god, heaven, hell...
|
| Androcles
|
|
| Do you suppose the event could generate a powerful enough burst of
| radiation to penetrate the Earth itself and kill those even on the
| night side, or would those people have a few more hours to live? Or
| could the shock wave blow away the entire Earth's atmosphere like down
| off a thistle?

A termite hill
http://www.africanculture.dk/gambia/...ermitehill.jpg
with termites in it
http://www.uky.edu/Ag/Entomology/ent.../termwrkrs.jpg
once stood he
http://www.normanzimmerman.com/Meteo...2005%20035.jpg
http://www.barringercrater.com/science/

I suggest you learn Venus and Mercury are about the same size as Earth,
(a green/blue apple, a white golf or tennis ball and a walnut), examine these
images and answer that question for yourself.
http://images.google.co.uk/images?hl=en&q=Venus+transit
http://images.google.co.uk/images?hl...ercury+transit

If the Earth were the size of an apple, the Sun would be the size
of the World Trade Centre in the Big Apple before it was hit by
a plane.
What happened to that apple someone took in his briefcase
for his lunch on 9/11?
If you look carefully, you might see the apple:
http://video.google.co.uk/videoplay?...62871641918799

"What if..." --- sigh
Androcles.

Ben Bradley writes:

In the newsgroups: alt.astronomy, rec.arts.sf.science, sci.astro,
sci.space.policy and soc.history.what-if,
On 23 Nov 2006 19:40:59 -0600, The Chief Instigator
wrote:

"Double-A" writes:

paulaireilly wrote:
Sorcerer wrote:
| How dangerous
| it could be for life on Earth?

Depends on the star and how close it passes.

I wonder what effect a direct collision between a sun sized star and
the Sun would have on life on Earth?

Haha!

Double-A

We'd know about it eight and a half minutes later...and shortly after that,
we wouldn't be around to wonder about it.

That's when we would see it happen. If the hypervelocity star were
going at 99 percent of lightspeed, that's also about the time we'd
find out about it.
But the fastest speed in the original post is "4000 kilometres
per second", slow enough for astronomers to notice it by the time it
becomes the brightest star in the night sky, and have perhaps a few
weeks or months to contemplate the fact that it's heading straight
into the middle of the Solar System. And this isn't like an
Earth-grazing asteroid, where it's feasible to send a rocket up to
nudge it off of a collision course. At that speed it would push the
the Sun right out of the Solar System, with whatever's left of the two
stars moving out from the Sun's (former) position at an average of
2,000 km/s (if I calculate correctly, that's 1 AU every 8 days).

Let's see...1 AU is roughly 150 million kilometers, and at 2000 km/sec it'd
take 75,000 seconds, which is 20 hours and 50 minutes, which would work out to
being 7 AU away in a 143 hours - an hour short of six days.

But presuming the immense solar flares (surely orders of magnitude
above anything we've seen) don't kill everyone (perhaps there's a
chance in mineshafts, if earthquakes aren't triggered by all this),
and the other star doesn't push the Sun or some parts of it into or
too near Earth, within a few weeks our new Sun(s) will be dimming as
it goes away, and the Earth goes on a straight path at its former
orbital speed of 13 miles per second. For anyone who's still alive,
it'll be a long, cold ride.

But even a star passing the Solar System "in interstellar space"
may have a negative effect on the Oort Cloud, as Frank Glover said.

From Wikipedia:
"The Oort cloud, alternatively termed the Öpik-Oort Cloud, is a
postulated spherical cloud of comets situated about 50,000 to 100,000
AU from the Sun. This is approximately 2000 times the distance from
the Sun to Pluto or roughly one light year, almost a quarter of the
distance from the Sun to Proxima Centauri, the star nearest the Sun."

Close enough, and if it's out there, that could have some effects that would
take a while to manifest themselves - even if it's passing by about 1.5
lightyears away, it could wrench objects in the Oort into a course that would
bring them into the System. (That's what's called the bonus can of worms. :-)
Fortunately, the odds are very slim...but since the probability isn't zero, we
should be making efforts to learn what's out there, anyway.

--
Patrick "The Chief Instigator" Humphrey ) Houston, Texas
chiefinstigator.us.tt/aeros.php (TCI's 2006-07 Houston Aeros)
LAST GAME: San Antonio 4, Houston 2 (November 21)
NEXT GAME: Friday, November 24 vs. San Antonio, 7:35

"tracy" wrote in message
oups.com...
According to this article, the mysterious super-high speed stars are
more numerous and fastest than previously though. What if one of these
"hypervelocity" stars came through Sun's neighborhood? How dangerous
it could be for life on Earth?

What would be safe distance a star moving at about 700 - 1000 km/s
could get near Sun without disrupting the planetary system?


Not sure about that, this is related to an interesting photo on today's APOD

http://antwrp.gsfc.nasa.gov/apod/ap061124.html

Alpha Cam, allegedly creating a 'bow wave' in the interstellar medium up to
10 light years ahead of its position

OG wrote:
"tracy" wrote in message
oups.com...
According to this article, the mysterious super-high speed stars are
more numerous and fastest than previously though. What if one of these
"hypervelocity" stars came through Sun's neighborhood? How dangerous
it could be for life on Earth?

What would be safe distance a star moving at about 700 - 1000 km/s
could get near Sun without disrupting the planetary system?


Not sure about that, this is related to an interesting photo on today's APOD

http://antwrp.gsfc.nasa.gov/apod/ap061124.html

Alpha Cam, allegedly creating a 'bow wave' in the interstellar medium up to
10 light years ahead of its position


How does an attractive object like a star create a bow shock? The bow
of a ship creates a bow shock because it repulses the water. UNLESS,
we are seeing an anti-matter star plowing through regular matter and
repulsing it with an anti-gravity interaction!

Double-A