Categories
astronomy Cosmology Creation/evolution Physics

First ever gravitationally lensed supernova

— a problem for the biblical creationist model?

This image shows the huge galaxy cluster MACS J1149+2223, whose light took over 5 billion years to reach us. The huge mass of the cluster and one of the galaxies within it is bending the light from a supernova behind them and creating four separate images of it. The light has been magnified and distorted due to gravitational lensing and as a result the images are arranged around the elliptical galaxy in a formation known as an Einstein cross. A close-up of the Einstein cross is shown in the inset.
Figure 1: Galaxy cluster MACS J1149+2223,  over 5 billion light-years distant. The huge mass of the cluster and one of the galaxies within it is bends the light from a supernova behind them and creating four separate images (arrows in inset). The light has been magnified and distorted due to gravitational lensing and as a result the images are arranged around the elliptical galaxy in a formation known as an Einstein cross. A close-up of the Einstein cross is shown in the inset. Credit: NASA & ESA

In March 2015  it was reported that “[a]stronomers using the NASA/ESA Hubble Space Telescope have, for the first time, spotted four images of a distant exploding star. The images are arranged in a cross-shaped pattern by the powerful gravity of a foreground galaxy embedded in a massive cluster of galaxies.”1 See galaxy in inset in Fig. 1, which has been enlarged in Fig. 2.

This image shows four different images of the same supernova whose light has been distorted and magnified by the huge galaxy cluster MACS J1149+2223 in front of it. The huge mass of the cluster and one of the galaxies within it is bending the light from a supernova behind them and creating four separate images of the supernova. The light has been magnified and distorted due to gravitational lensing and as a result the images are arranged around the elliptical galaxy in a formation known as an Einstein cross.
Figure 2: This image shows four different images of the same supernova whose light has been distorted and magnified by the huge galaxy cluster MACS J1149+2223 in front of it. The huge mass of the cluster and one of the galaxies within it is bending the light from a supernova behind them and creating four separate images of the supernova. The light has been magnified and distorted due to gravitational lensing and as a result the images are arranged around the elliptical galaxy in a formation known as an Einstein cross. Credit: NASA & ESA

Astronomers were looking at a massive elliptical galaxy (Fig .2) and its associated galaxy cluster MACS J1149+2223 (Fig. 1), which is supposedly at a distance in the universe such that the light from the galaxy should take more than 5 billion years to reach Earth. They then found something that has never been seen before. The huge mass of the elliptical galaxy and the cluster is believed to bend the light from a much more distant galaxy where a supernova was occurring. The image of the supernova then is seen as an Einstein cross made from 4 separate images of the same supernova, heic1505, also named Refsdal. In Fig. 1 arrows indicate the 4 images. Fig. 1. shows a wide view of the cluster and the elliptical galaxy with the alleged identical 4 supernova images around it.

Now, a new claim has been made. Because the path lengths for the 4 different images of the supernova are not equal, due to the lensing effect of the massive cluster, the travel time for the light along each path is different. Since some paths are longer than others it has been predicted that the light signal for one of them is greatly delayed (by about a year) over the others. Therefore astronomers are excited by the prospect of seeing the increasing light curve of the supernova explosion once again just like they have already observed.

Using various models of the cluster acting as a lens, astronomers have made a consistent set of predictions for when the next image will appear. Hubble’s gaze will now periodically be fixed on the skies in anticipation of once again observing Refsdal. The next image of this extraordinary event is expected to peak in the first third of 2016.2

This illustration shows how four different images of the same supernova were created when its light was distorted and magnified by the huge galaxy cluster MACS J1149+2223 in front of it. The light has been magnified and distorted due to gravitational lensing and as a result the images are arranged around the elliptical galaxy in a formation known as an Einstein cross. The massive galaxy cluster focuses the supernova light along at least three separate paths, and then when one of those light paths happens to be precisely aligned with a single elliptical galaxy within the cluster, a secondary lensing effect occurs. The dark matter associated with the elliptical galaxy bends and refocuses the light into four more paths, generating the rare Einstein cross pattern that the team observed.
Figure 3: This illustration shows how four different images of the same supernova were created when its light was distorted and magnified by the huge galaxy cluster MACS J1149+2223 in front of it. The massive galaxy cluster focuses the supernova light along at least three separate paths, and then when one of those light paths happens to be precisely aligned with a single elliptical galaxy within the cluster, a secondary lensing effect occurs (lower inset). Credit: NASA & ESA.

Challenge to a creationist cosmological model?

Now I have been challenged via Twitter (see below) that the biblical creationist ASC model3 has a problem because that model says that all incoming light from the cosmos to Earth travels at infinite speed. This is a reference to the one-way speed of light. Therefore if the supernova is the same one for all 4 images how is it possible that the light can be delayed in one path by any amount, let alone a year, when it travels at infinite speed?

DocScience twitter challenge

The answer to this is straightforward and comes from a correct understanding of the actual one-way speed of light concept. It should be noted that the Anisotropic Synchrony Convention (ASC) is as valid a choice of a timing convention as is the Einstein Synchrony Convention (ESC), which assumes isotropic speed of light, c. Therefore it is only a coordinate transformation and the physics under either the ESC (which is standard in cosmology today) or the ASC is unchanged.

The ASC assumes a particular anisotropy in the one-way speed of light in vacuum. The inbound speed toward the observer is infinite, but light speed incident at an arbitrary angle, θ, to the observer is given by:

c = c0/(1-cosθ),                                                (1)

where c0 is the canonical speed of light (c0 = 299,792 km/s) as determined from a two-way speed of light measurement. Thus θ = 0 degrees means incident on the observer and θ = 180 degrees means moving away from the observer. At 90 degrees or transverse to the observer the speed of light is the canonical speed c0, the same as the two-way isotropic speed of light.

Looking at the trigonometry in the lower image of Fig. 3, with the 4 light paths shown, it is clear to see that the radial components of the paths from the source to the observer are all identical. This is further illustrated by two light paths “A” and “B” in Fig. 4.  What is different is their transverse components, which represent the deviations of these paths from a “direct line of sight” geometrical distance. The deviations are produced by the gravitational lens effect of the elliptical galaxy, bending the light around it. These deviations add increased path lengths and longer travel times. The reason the travel times are longer is because the one-way speed of light (as defined by the choice of the ASC convention) is the canonical speed c0 for those components of the distance in those paths. Therefore if the paths were all “straight in” without deviation all 4 light beams would arrive at the same time, instantly, but there would be no gravitationally lensed Einstein cross either. What the ASC model expects in this case is that the relative travel times, at speed c0, along paths transverse (at 90 degrees) to the observer are what makes the differences in the arrival times of the 4 supernova light signals.

This result is the same as under the ESC assumption, as expected. Consider in the case of the ESC the 4 “straight in” without deviation components of the light beams would all arrive at the same time travelling at the same speed c0 and exactly the same distance. Again it is only the relative travel times, at speed c0, along paths transverse (at 90 degrees) to the observer that make any differences in the arrival times of the 4 supernova light signals.

This may be better understood from Fig. 4. The explosion is the supernova source and the eyes are the observer. All observations are in the rest frame of the observer. For both ESC and ASC the travel time along any path, A or B in this case, is the total distance divided by the speed of light along that path. The travel time along path A is tA = a/c, and along path B the travel time is tB = (b1+b2)/c. Under ESC c = c0 regardless of direction (isotropic), but under ASC c is determined from equation (1) above (anisotropic).

It follows from Fig. 4 that any extra-travel time due to a deviation from the straight path (path A) is found only in the transverse component (distance d). Thus irrespective of the simultaneity convention chosen the additional travel time to Earth is,

tB – tA = 2d/c = 2d/c0.                                       (2)

This is because for path B over the segment b1 the light has an additional transverse travel time component d/c0 and over the segment b2 it again has an additional transverse travel time component d/c0 to bring the beam back in line to arrive at the observer. As expected the physics is unchanged regardless of which convention is chosen. This is because under both conventions the transverse speed of light c = c0.Path A and B illustrated

 

Conclusion

This latest alleged discovery of a gravitational lensed supernova, with separate 4 images and different paths to Earth, even if correct, is not a problem for the biblical creationist ASC cosmology. It is no disproof of an infinite one-way speed of light towards the observer on Earth. Nor should it be, because a different choice of a timing or simultaneity convention, apart from the one that Einstein chose, can have no bearing on the physics. It is simply a different convention and without assuming a convention one cannot know the speed of light, regardless of whether you assume it isotropic or not.

References

  1. Hubble sees multiple images of a supernova for the very first time, March 5, 2015
  2. Astronomers get once-in-a-lifetime opportunity to predict supernova, November 13, 2015.
  3. Synopsis: A biblical creationist cosmogony, March 9, 2015.

Additional Reading

  1. R. Newton, Distant starlight and Genesis: conventions of time measurement, Journal of Creation 15, no. 1: 80-85, 2001; J.P. Lisle, Anisotropic Synchrony Convention—A Solution to the Distant Starlight Problem, Answers Research Journal 2:191–207, 2010.
  3. J.G. Hartnett,  Synopsis: A biblical creationist cosmogony
  4. J.G. Hartnett,  Expansion of space – a dark science
  5. J.G. Hartnett,  A biblical creationist cosmogony
  6. J.G. Hartnett,  Speculation on redshift in a created universe
  7. J.G. Hartnett,  Supernova remnants and the age of the Universe

By John Gideon Hartnett

Dr John G. Hartnett is an Australian physicist and cosmologist, and a Christian with a biblical creationist worldview. He received a B.Sc. (Hons) and Ph.D. (with distinction) in Physics from The University of Western Australia, W.A., Australia. He was an Australian Research Council (ARC) Discovery Outstanding Researcher Award (DORA) fellow at the University of Adelaide, with rank of Associate Professor. Now he is retired. He has published more than 200 papers in scientific journals, book chapters and conference proceedings.

8 replies on “First ever gravitationally lensed supernova”

Thanks for the insight in explaining this event. I was wondering if parallax comes into play in this event at all, allowing astronomers to better measure the distance of either earth to the galaxy serving as a lens, or earth to the super nova behind it, or the super nova to the galaxy, once the delayed event is observed, confirming or refuting the Hubble distance.

kind regards,

Like

John,
Please, help my ignorance on this topic. I would like to get your comment to a potential experiment. If I synchronize two end points, A and B, to the same time reference, for example an atomic clock or GPS or similar. If I would then take A and B sufficiently far from each other. I would then send a radio or light signal from A towards B and register the time it left A and separately the time it reaches B. I would then repeat the experiment in the other direction. Finally, I would compare the time stamps from A and B and notice that the send and receive times differ similarly in either direction. Does an experiment like this have any relevance to the topic of ASC versus ESC?
Regards,
Markku

Like

Markku, Yes it does. Your experiment is a two-way speed of light measurement. To compute the travel time you have to send a light signal from A to B and then B to A. You don’t need a clock at both ends, a mirror would do. But if you have two clocks it is the same thing, even if you initially synchronise both clocks before separating them. To have knowledge of their synchrony once separated you still have to send light signals both ways. Under ESC the assumption is made that the speed of light is isotropic and since you can only measure the total time for travel between A to B and then back to A it gives the speed of light in either direction. But the assumption is necessary to interpret the measurements.

Like

By Post Author

In my opinion ASC is invalid because it is self-contradictory:

Consider an observer standing at the North end of an optical bench and making measurements on the one-way speed of light. ASC says that he should synchronize the clock at each end of the table so that the *incoming* photons emitted from the South end arrive at the North end in zero time – which will mean that *outgoing* photons which are emitted from the North end and travel South take roughly double the time that the “speed of light” suggests they should take.

However if a second ASC believer wanders in and stands at the South end of the optical bench he will insist that the clocks have been synchronized incorrectly because now his *outgoing* photons are travelling at infinite speed whereas his *incoming* photons are only travelling at c/2. What is worse is that if the first observer swaps ends he now has to agree with the second observer that his initial synchronization was completely wrong!

So summarizing the problem – the one-way speed of photons is just as easy to measure as the one-way speed of any other particle or object in creation. The only debate is how to synchronize the separated clocks that are necessary to make the measurement. The problem with ASC is that it requires an observer-centric synchronization such that as the observer moves with respect to his clocks, so he has to change their synchronization to match his new position among them. Separated observers can never agree on light travelling along the line between them – because incoming light for one is outgoing light for the other! (I think there are worse problems with the ASC idea, but this is maybe the most obvious and easiest to explain).

Like

John, You are entitled to your opinion, though I disagree. However, it is impossible to measure the one-way speed of light, that is, without an unprovable assumption regarding clock synchronisation. It is beyond physics to do so, and hence, it may be that it is not a physical meaningful parameter. To claim anything different to that would not be the truth.

However, like it or not, choosing the ASC as the clock synchronisation convention of choice for a particular measurement is as equally valid as choosing the ESC. Einstein was fully aware of that fact as were/are many others who followed him.

But let me cite the author, Jason Lisle, of the current ASC creationist model, with respect to a big problem of using the ESC:

And to drill home the absurdity of the Bible using the ESC convention, I’d like to examine the verse you cited – 2 Peter 3:7. Since virtually everyone before Galileo considered the universal “now” to be “what we currently see,” there can be little doubt that people would have interpreted the verse to mean just that – the present heavens as we see them now in real time (by the ASC). Now if God really meant “the present” according to the ESC (in which the present universe is a totally unobservable mathematical construct) then we must ask “relative to whom” because ESC is velocity-dependent, and observers on earth have very different velocities due to earth’s rotation. The Lorentz transformations show that the present heavens will be different for different observers depending on where they are on earth – a difference of tens of thousands of years! This principle is called the “relativity of simultaneity.”

For more on that read JASON LISLE DEFENDS HIS ASC MODEL

But in all this I think you are losing sight of one important point, both of these, ASC and ESC, are merely timing conventions. One must choose one. The Universe provides no absolute reference frame, nor an absolute timing convention. We are free to choose, and that is done according to which experiment or observation it best suits.

Like

By Post Author

Comments are closed.