Mars, Moon, solar system could be littered with alien artifacts

"Boffins' calculations offer answer to Fermi Paradox"

See:

http://www.theregister.co.uk/2011/11...could_be_here/

wrote:
"Boffins' calculations offer answer to Fermi Paradox"

See:

http://www.theregister.co.uk/2011/11...could_be_here/

The article posits L5 (and consequently also L4) as artifact catchers. Which
presents the possibility that there mere existence is more effective than all
of our META surveys because of their longevity...

Interesting...

You could almost write a SF story about the first recon mission to L5 finding
an alien artifact adrift there. *almost* ...Don't hover over and stare at
those oblong shapes too long tho... ;-)

OTOH it would be interesting to launch unmanned probes to L5 and L4 just to
survey. Or even better, have we ever done any ground-based radar imaging of
those areas to see what's been swept up already? It seems possible there might
be stuff (like small asteroids or some degree of "space dust") already stuck
there, perhaps stuff left over from the primordial solar disk?

Dave

On 30/11/2011 5:47 PM, David Spain wrote:
wrote:
"Boffins' calculations offer answer to Fermi Paradox"

See:

http://www.theregister.co.uk/2011/11...could_be_here/


The article posits L5 (and consequently also L4) as artifact catchers.
Which presents the possibility that there mere existence is more
effective than all of our META surveys because of their longevity...

Interesting...

You could almost write a SF story about the first recon mission to L5
finding an alien artifact adrift there. *almost* ...Don't hover over and
stare at those oblong shapes too long tho... ;-)

OTOH it would be interesting to launch unmanned probes to L5 and L4 just
to survey. Or even better, have we ever done any ground-based radar
imaging of those areas to see what's been swept up already? It seems
possible there might be stuff (like small asteroids or some degree of
"space dust") already stuck there, perhaps stuff left over from the
primordial solar disk?

Dave

It doesn't seem very likely to me that an inert object arriving from
interstellar space would end up at a Lagrangian point. After all, absent
some significant interaction with a planet, it has solar escape
velocity, and will most probably go right through the system and head
back out to the stars with just a change of direction.

There are an awful lot of comets, and they behave in much the same way
(except that they're probably already in orbit about the sun). How many
of them appear to get captured in Lagrangian points?

Even if an dead alien spacecraft interacts gravitationally with a planet
so as to be captured in the solar system, it'll be a very small object
in some random orbit about the sun, and next to impossible to locate,
even if we tried.

As for finding plaques on the moon, how much would be left after impact?

Sylvia.

On Nov 30, 7:43*am, Sylvia Else wrote:
On 30/11/2011 5:47 PM, David Spain wrote:





wrote:
"Boffins' calculations offer answer to Fermi Paradox"

See:

http://www.theregister.co.uk/2011/11...lien_artifacts....

The article posits L5 (and consequently also L4) as artifact catchers.
Which presents the possibility that there mere existence is more
effective than all of our META surveys because of their longevity...

Interesting...

You could almost write a SF story about the first recon mission to L5
finding an alien artifact adrift there. *almost* ...Don't hover over and
stare at those oblong shapes too long tho... ;-)

OTOH it would be interesting to launch unmanned probes to L5 and L4 just
to survey. Or even better, have we ever done any ground-based radar
imaging of those areas to see what's been swept up already? It seems
possible there might be stuff (like small asteroids or some degree of
"space dust") already stuck there, perhaps stuff left over from the
primordial solar disk?

Dave

It doesn't seem very likely to me that an inert object arriving from
interstellar space would end up at a Lagrangian point. After all, absent
some significant interaction with a planet, it has solar escape
velocity, and will most probably go right through the system and head
back out to the stars with just a change of direction.

There are an awful lot of comets, and they behave in much the same way
(except that they're probably already in orbit about the sun). How many
of them appear to get captured in Lagrangian points?

Even if an dead alien spacecraft interacts gravitationally with a planet
so as to be captured in the solar system, it'll be a very small object
in some random orbit about the sun, and next to impossible to locate,
even if we tried.

As for finding plaques on the moon, how much would be left after impact?

Sylvia.- Hide quoted text -

- Show quoted text -

maybe the ailiens are already observing us from the L points?

Le 30/11/11 14:34, bob haller a écrit :
On Nov 30, 7:43 am, Sylvia wrote:
On 30/11/2011 5:47 PM, David Spain wrote:





wrote:
"Boffins' calculations offer answer to Fermi Paradox"

See:

http://www.theregister.co.uk/2011/11...lien_artifacts...

The article posits L5 (and consequently also L4) as artifact catchers.
Which presents the possibility that there mere existence is more
effective than all of our META surveys because of their longevity...

Interesting...

You could almost write a SF story about the first recon mission to L5
finding an alien artifact adrift there. *almost* ...Don't hover over and
stare at those oblong shapes too long tho... ;-)

OTOH it would be interesting to launch unmanned probes to L5 and L4 just
to survey. Or even better, have we ever done any ground-based radar
imaging of those areas to see what's been swept up already? It seems
possible there might be stuff (like small asteroids or some degree of
"space dust") already stuck there, perhaps stuff left over from the
primordial solar disk?

Dave

It doesn't seem very likely to me that an inert object arriving from
interstellar space would end up at a Lagrangian point. After all, absent
some significant interaction with a planet, it has solar escape
velocity, and will most probably go right through the system and head
back out to the stars with just a change of direction.

There are an awful lot of comets, and they behave in much the same way
(except that they're probably already in orbit about the sun). How many
of them appear to get captured in Lagrangian points?

Even if an dead alien spacecraft interacts gravitationally with a planet
so as to be captured in the solar system, it'll be a very small object
in some random orbit about the sun, and next to impossible to locate,
even if we tried.

As for finding plaques on the moon, how much would be left after impact?

Sylvia.- Hide quoted text -

- Show quoted text -

maybe the ailiens are already observing us from the L points?


Any aliens know since millions of years that there is life on earth.
The atmosphere of our planet has way too much oxygen. Something must be
producing all that oxygen.

All alien civilizations with a level of telescope technology that we
will have in 10 years from now have been able to analyze the composition
of earth atmosphere and deduce that this planet is inhabited.

This signal has been broadcasting life presence since 500-1000 million
years.

Another signal is the electromagnetic noise that we broadcast in all
directions. This signal has a radius of at least 60 light years.

This two signals combined make for an interesting target for
alien anthropologist and scientists interested in primitive
civilizations like ours.

And yet another signal is the light we emit at night, visible
with a small scope from Mars already.

Conclusion:

We are an interesting target, and all alien civilizations with
just 100 years advance from us are aware of our presence. We
have been broadcasting our presence like a newborn crying
aloud.

jacob

Sylvia Else wrote:
It doesn't seem very likely to me that an inert object arriving from
interstellar space would end up at a Lagrangian point. After all, absent
some significant interaction with a planet, it has solar escape
velocity, and will most probably go right through the system and head
back out to the stars with just a change of direction.


To be fair the article mentions solar Lagrange points. My cis-Lunar Lagrange
speculation was an extrapolation from the article. But your skepticism would
just as well apply to those too.

There are an awful lot of comets, and they behave in much the same way
(except that they're probably already in orbit about the sun). How many
of them appear to get captured in Lagrangian points?

Even if an dead alien spacecraft interacts gravitationally with a planet
so as to be captured in the solar system, it'll be a very small object
in some random orbit about the sun, and next to impossible to locate,
even if we tried.

But perhaps not as hard as SETI? I could imagine a program to search for radar
returns of objects at high solar ecliptic inclination orbits, which would be
less likely to have a solar origin (Oort cloud objects excluded). Perhaps part
of a planetary defense system against rogue asteroids? For all I know, some
surveys may have already been done, Google is my friend.


As for finding plaques on the moon, how much would be left after impact?


Yeah, and if the artifact *can* survive that kind of impact would we want them
to *know* about us?

But let's put the LGM aspect to rest. I'm far more interested in the local
space aspects of the stable Lagrange points (L4/L5). What is the likely-hood
that they have collected primordial solar dust or having collected NEO space
dust in general? Not only during Earth and Moon formative stages, but also say
from stuff kicked up by some of the more violent Earth or Lunar meteor
strikes? It may turn out these areas are not as empty as we think and might
present a larger micro-meteorite threat to HSF endeavors there than is
currently presumed.

Wouldn't this question be easily resolved via ground-based observation either
optically or via microwave? Has it already been done?

Dave

Fred J. McCall wrote:

So why haven't we seen them?


Fred,

For the same reason I don't call my neighbor's dog over to do his business in
my yard....

;-)

Dave

On 1/12/2011 3:03 AM, David Spain wrote:
Sylvia Else wrote:
It doesn't seem very likely to me that an inert object arriving from
interstellar space would end up at a Lagrangian point. After all,
absent some significant interaction with a planet, it has solar escape
velocity, and will most probably go right through the system and head
back out to the stars with just a change of direction.


To be fair the article mentions solar Lagrange points. My cis-Lunar
Lagrange speculation was an extrapolation from the article. But your
skepticism would just as well apply to those too.

There are an awful lot of comets, and they behave in much the same way
(except that they're probably already in orbit about the sun). How
many of them appear to get captured in Lagrangian points?

Even if an dead alien spacecraft interacts gravitationally with a
planet so as to be captured in the solar system, it'll be a very small
object in some random orbit about the sun, and next to impossible to
locate, even if we tried.

But perhaps not as hard as SETI? I could imagine a program to search for
radar returns of objects at high solar ecliptic inclination orbits,
which would be less likely to have a solar origin (Oort cloud objects
excluded). Perhaps part of a planetary defense system against rogue
asteroids? For all I know, some surveys may have already been done,
Google is my friend.

At least with SETI you know to point your telescope at a star. When
trying to find an object using radar, you have the problem that the
wider the beam the lower the sensitivity, and the narrower the beam, the
longer it takes to examine a given patch of sky in detail (and the
target objects have unknown apparent motions, to make matters worse).

Also, the return time for a radar pulse in this scenario reaches half an
hour even to examine the space inside Earth's orbit. Maybe there are
clever ways of dealing with this, but at first sight, it appears to me
that you have to emit the pulse, and then keep the antenna pointed in
the same direction for a period that depends on how deeply into space
you're trying to look. It's not like picking up enemy aircraft
approaching a country's border.

Sylvia.

In sci.space.policy message
om, Wed, 30 Nov 2011 01:47:58, David Spain posted:

wrote:
"Boffins' calculations offer answer to Fermi Paradox"
See:
http://www.theregister.co.uk/2011/11...alien_artifact
s_could_be_here/

The article posits L5 (and consequently also L4) as artifact catchers.
Which presents the possibility that there mere existence is more
effective than all of our META surveys because of their longevity...

To be meaningful, an article referring to a Lagrange Point needs to
indicate sufficiently clearly which secondary body is involved.

The Sun, for example, probably has about 40 significant points, for the
planets known before Pluto. Points associated with smaller bodies seem
likely to have too much perturbation from bigger bodies, but perhaps
not.

The Register article acknowledges the large number of (implicitly) L4 &
L5 points in the Solar System.

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