Can we detect a blueshift of -c?
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From: Brad Guth on 23 Apr 2010 17:17 On Apr 23, 10:36 am, Double-A <double...(a)hush.com> wrote: > On Apr 22, 9:31 pm, Brad Guth <bradg...(a)gmail.com> wrote: > > > > > On Apr 22, 1:33 pm, "Greg Neill" <gneil...(a)MOVEsympatico.ca> wrote: > > > > Brad Guth wrote: > > > > How about photons from a vibrant 10 solar mass star that's situated > > > > well within our visual detection horizon of 13.7e9 ly, but trekking > > > > directly towards us at -c? > > > > It can't. Nothing physical within our horizon can be > > > observed to move at or above c. Close to c, sure, but > > > not at or above. > > > > The best a body can do is approach c with respect to > > > observers in its proximity (within the local region of > > > space moving with the Hubble flow). Every non-local > > > observer (such as us sitting a great distance away from > > > that region in our own local region) sees that region > > > of space moving away in bulk according to the Hubble > > > expansion, thus decreasing any net speed of approach. > > > I wasn't asking for your subjective opinion of physics. > > > I was asking about photons from a vibrant 10 solar mass star that's > > situated well within our visual detection horizon of 13.7e9 ly, > > trekking directly towards us at -c. How would we ho about detecting > > this 100% blue-shift? > > > ~ BG > > Any star moving towards us at the speed of light would be a black hole > relative to us (infinite mass). Also every photon it emitted in our > direction would also be a black hole, because 100 percent blue-shift > would cause the infinite energy resulting from that shift to be > confined to an infinitely small area, thus resulting in event horizons > forming. Unless there proves to be some truth to long range variable > speed light theories, there would be no way we could detect it before > it hit us! > > Double-A I'll buy that, except there should be a fairly large radii Oort cloud that could be detectable as we pass through or nearby. Our small and relatively passive sun supposedly has a light year radii worth of Oort cloud. ~ BG
From: Brad Guth on 23 Apr 2010 12:35 On Apr 23, 5:09 am, "Greg Neill" <gneil...(a)MOVEsympatico.ca> wrote: > Brad Guth wrote: > > On Apr 22, 1:33 pm, "Greg Neill" <gneil...(a)MOVEsympatico.ca> wrote: > >> Brad Guth wrote: > >>> How about photons from a vibrant 10 solar mass star that's situated > >>> well within our visual detection horizon of 13.7e9 ly, but trekking > >>> directly towards us at -c? > > >> It can't. Nothing physical within our horizon can be > >> observed to move at or above c. Close to c, sure, but > >> not at or above. > > >> The best a body can do is approach c with respect to > >> observers in its proximity (within the local region of > >> space moving with the Hubble flow). Every non-local > >> observer (such as us sitting a great distance away from > >> that region in our own local region) sees that region > >> of space moving away in bulk according to the Hubble > >> expansion, thus decreasing any net speed of approach. > > > I wasn't asking for your subjective opinion of physics. > > > I was asking about photons from a vibrant 10 solar mass star that's > > situated well within our visual detection horizon of 13.7e9 ly, > > trekking directly towards us at -c. How would we ho about detecting > > this 100% blue-shift? > > See my first paragraph above. > > If your observed star is relatively close by, it's observed > velocity will be limited by an upper bound approaching c. > The further away it is (and the closer it gets to our > cosmic horizon), the motion due to the expansion of the > space between us and it has to be added to its motion > through space, decreasing the net observed velocity. > > Near the horizon, a body moving at near c in its local space > in a direction towards us will have a net velocity near > zero (the best it could do would be to stand still with > respect to us), and so its red shift would be very small. > > There is no way for a body to be observed moving towards us > at c. That's exactly what Id thought. If we're moving away or towards other mass at c, we'd be oblivious to realizing its existence. I understand there's a few rogue stars moving at 1500 km/sec, and it's thought possible that stars further out could easily be moving at .5c, so what if another star were moving towards the other at .5c, making their mutual closing velocity c. Due to their relative closing velocity being c, could either of those fast moving stars notice the other? (I don't think so) It seems anything moving away or towards us at c (relative to us) becomes stealth/invisible. This simply means were always at some degree of risk unless fast moving exogravity can be detected. A neutron star or black hole closing in on us, even if it were passing outside of Pluto could be a cosmic form of fatal attraction, whereas just the gravitational shockwave of one light year radii alone could perturb and/or traumatize most everything about our solar system. ~ BG
From: Brad Guth on 23 Apr 2010 13:10 On Apr 23, 5:37 am, "J. Clarke" <jclarke.use...(a)cox.net> wrote: > On 4/23/2010 8:09 AM, Greg Neill wrote: > > > > > Brad Guth wrote: > >> On Apr 22, 1:33 pm, "Greg Neill"<gneil...(a)MOVEsympatico.ca> wrote: > >>> Brad Guth wrote: > >>>> How about photons from a vibrant 10 solar mass star that's situated > >>>> well within our visual detection horizon of 13.7e9 ly, but trekking > >>>> directly towards us at -c? > > >>> It can't. Nothing physical within our horizon can be > >>> observed to move at or above c. Close to c, sure, but > >>> not at or above. > > >>> The best a body can do is approach c with respect to > >>> observers in its proximity (within the local region of > >>> space moving with the Hubble flow). Every non-local > >>> observer (such as us sitting a great distance away from > >>> that region in our own local region) sees that region > >>> of space moving away in bulk according to the Hubble > >>> expansion, thus decreasing any net speed of approach. > > >> I wasn't asking for your subjective opinion of physics. > > >> I was asking about photons from a vibrant 10 solar mass star that's > >> situated well within our visual detection horizon of 13.7e9 ly, > >> trekking directly towards us at -c. How would we ho about detecting > >> this 100% blue-shift? > > > See my first paragraph above. > > > If your observed star is relatively close by, it's observed > > velocity will be limited by an upper bound approaching c. > > The further away it is (and the closer it gets to our > > cosmic horizon), the motion due to the expansion of the > > space between us and it has to be added to its motion > > through space, decreasing the net observed velocity. > > > Near the horizon, a body moving at near c in its local space > > in a direction towards us will have a net velocity near > > zero (the best it could do would be to stand still with > > respect to us), and so its red shift would be very small. > > > There is no way for a body to be observed moving towards us > > at c. > > If we accept Guth's premise that something is coming toward us at c, > leaving aside the issue of how that came to be, then it's not going to > be detectable in time to do anything useful since it's going to arrive > simultaneously with any light coming off it, so what's the point of > trying to detect it? If it exists we will be well aware of it for > perhaps a picosecond. Depending on its mass, the gravitational shockwave of perhaps one light year radii could represent a 2 year window of realizing its passing existence. Of course we'd likely be vaporized or at least badly affected before we ever realized what just happened. ~ BG
From: Double-A on 23 Apr 2010 13:36 On Apr 22, 9:31 pm, Brad Guth <bradg...(a)gmail.com> wrote: > On Apr 22, 1:33 pm, "Greg Neill" <gneil...(a)MOVEsympatico.ca> wrote: > > > > > > > Brad Guth wrote: > > > How about photons from a vibrant 10 solar mass star that's situated > > > well within our visual detection horizon of 13.7e9 ly, but trekking > > > directly towards us at -c? > > > It can't. Nothing physical within our horizon can be > > observed to move at or above c. Close to c, sure, but > > not at or above. > > > The best a body can do is approach c with respect to > > observers in its proximity (within the local region of > > space moving with the Hubble flow). Every non-local > > observer (such as us sitting a great distance away from > > that region in our own local region) sees that region > > of space moving away in bulk according to the Hubble > > expansion, thus decreasing any net speed of approach. > > I wasn't asking for your subjective opinion of physics. > > I was asking about photons from a vibrant 10 solar mass star that's > situated well within our visual detection horizon of 13.7e9 ly, > trekking directly towards us at -c. How would we ho about detecting > this 100% blue-shift? > > ~ BG Any star moving towards us at the speed of light would be a black hole relative to us (infinite mass). Also every photon it emitted in our direction would also be a black hole, because 100 percent blue-shift would cause the infinite energy resulting from that shift to be confined to an infinitely small area, thus resulting in event horizons forming. Unless there proves to be some truth to long range variable speed light theories, there would be no way we could detect it before it hit us! Double-A
From: Brad Guth on 22 Apr 2010 09:29
On Apr 21, 11:25 pm, "Peter Webb" <webbfam...(a)DIESPAMDIEoptusnet.com.au> wrote: > "Brad Guth" <bradg...(a)gmail.com> wrote in message > > news:90d95c55-3fda-4e4a-9df7-8bf39290bed1(a)m25g2000prj.googlegroups.com... > On Apr 21, 10:58 pm, "Peter Webb" > > <webbfam...(a)DIESPAMDIEoptusnet.com.au> wrote: > > Some parts of the Universe are moving towards us at speed c. > > > Some of the light from other galaxies, for example. > > > We can know nothing about this light until it actually reaches us. No > > information (eg that light was emitted by a distant galaxy) can travel > > faster than c. > > Perhaps as far as we know, yet gravity and the information it > represents seems to be worth at least 2c. > > ______________________ > > I think its worth much more than 2 cents. If nothing else, it keeps the > earth in orbit around the Sun. I agree, gravity could be as fast as c2 (9e16 m/s). btw; whatever happened to those planets orbiting Sirius(B)? ~ BG |