Jonathan Silverlight
June 3rd 04, 10:07 AM
In message >, alistair
> writes
>In message >, alistair
> writes
>>Dark energy could be causing the anomalous acceleration of pioneer
>10.
>>The solar system is surrounded by the spherical Oort cloud.If dark
>>energy consists of particles that flow into the galaxy, the Oort
>cloud
>>would shield
>>the solar system from those particles.However a gap in the Oort cloud
>>would allow some dark energy particles to flow into the solar system.
>
>
>ANDRE?MICHAUD wrote:
>
>There are a few problems with this idea :-)
>
>The paper by Anderson et al. which everyone cites is available online
>at
><http://xxx.lanl.gov/abs/http://www....gr-qc/0104064>. It has figures
>for the mass of
>the Pioneers (223 kg dry mass) and their surface area (or at least
>that
>of the dish antenna, which accounts for nearly all of it. It's a 2.74
>meter dish giving an area of 5.9 square meters.
>Also, the two Pioneers are going in nearly opposite directions.
>
>
>ALISTAIR writes:
>
>The mass and surface area you quote for Pioneer 10 would give an
>acceleration for Pioneer 10 that is roughly only one third smaller
>than the figure I calculated of 10^ -12 m/s^2.The correct figure NASA
>gives is 10^-10 m /s^2.
>However, if dark energy consists of particles with rest mass and these
>particles in our part of the Milky Way move at 99.9999 per cent the
>speed of light then there would be a relativistic mass increase by a
>factor of 10000 compared to the average expectation for dark energy
>mass which would have to be moving at a speed of around 1/3 that of
>light.Whether or not dark energy actually has a different mass density
>in galaxies compared to intergalactic space,I couldn't say.There is
>also the possibility that dark energy coming through a gap in the Oort
>cloud could pick up speed and mass if it has fluid like properties (
>though I think such a Bernouilli flow is unlikely given how large the
>mass increase would be).Both these factors could give the acceleration
>NASA quotes.The fact that the Pioneers are moving in opposite
>directions is irrelevant because the Oort cloud could have other gaps
>in it which allow dark energy particles into the solar sytem.
I hope you can sort out your attributions :-)
That's my reply you're quoting.
And I have an even bigger problem with the nature of the particles
making up your "dark energy". What sort of particle density are you
assuming - how many per m^3, for instance?
It looks to me as though you're proposing some sort of relativistic
particle, a new sort of cosmic ray, and I'm sure they would have been
detected in other ways. I don't see how they could be blocked by
anything in the outer solar system to produce the sort of localised flux
you need, or how they could deliver momentum to the Pioneers.
It gets worse! I've already mentioned Galileo, and the "Pioneer effect"
has also been reported for Ulysses. That's four probes in different
parts of the solar system.
> writes
>In message >, alistair
> writes
>>Dark energy could be causing the anomalous acceleration of pioneer
>10.
>>The solar system is surrounded by the spherical Oort cloud.If dark
>>energy consists of particles that flow into the galaxy, the Oort
>cloud
>>would shield
>>the solar system from those particles.However a gap in the Oort cloud
>>would allow some dark energy particles to flow into the solar system.
>
>
>ANDRE?MICHAUD wrote:
>
>There are a few problems with this idea :-)
>
>The paper by Anderson et al. which everyone cites is available online
>at
><http://xxx.lanl.gov/abs/http://www....gr-qc/0104064>. It has figures
>for the mass of
>the Pioneers (223 kg dry mass) and their surface area (or at least
>that
>of the dish antenna, which accounts for nearly all of it. It's a 2.74
>meter dish giving an area of 5.9 square meters.
>Also, the two Pioneers are going in nearly opposite directions.
>
>
>ALISTAIR writes:
>
>The mass and surface area you quote for Pioneer 10 would give an
>acceleration for Pioneer 10 that is roughly only one third smaller
>than the figure I calculated of 10^ -12 m/s^2.The correct figure NASA
>gives is 10^-10 m /s^2.
>However, if dark energy consists of particles with rest mass and these
>particles in our part of the Milky Way move at 99.9999 per cent the
>speed of light then there would be a relativistic mass increase by a
>factor of 10000 compared to the average expectation for dark energy
>mass which would have to be moving at a speed of around 1/3 that of
>light.Whether or not dark energy actually has a different mass density
>in galaxies compared to intergalactic space,I couldn't say.There is
>also the possibility that dark energy coming through a gap in the Oort
>cloud could pick up speed and mass if it has fluid like properties (
>though I think such a Bernouilli flow is unlikely given how large the
>mass increase would be).Both these factors could give the acceleration
>NASA quotes.The fact that the Pioneers are moving in opposite
>directions is irrelevant because the Oort cloud could have other gaps
>in it which allow dark energy particles into the solar sytem.
I hope you can sort out your attributions :-)
That's my reply you're quoting.
And I have an even bigger problem with the nature of the particles
making up your "dark energy". What sort of particle density are you
assuming - how many per m^3, for instance?
It looks to me as though you're proposing some sort of relativistic
particle, a new sort of cosmic ray, and I'm sure they would have been
detected in other ways. I don't see how they could be blocked by
anything in the outer solar system to produce the sort of localised flux
you need, or how they could deliver momentum to the Pioneers.
It gets worse! I've already mentioned Galileo, and the "Pioneer effect"
has also been reported for Ulysses. That's four probes in different
parts of the solar system.