Observing with Street Lights

Observing with Street Lights
Dark sky sites not always necessary to see the Milky Way (This image was taken ouside of a B&B in Julian, CA)

Friday, June 14, 2019

Didn't see any Falcon rocket exhaust; Looking at the moon with Nikon P1000; Hartlefest group; Big Bang and Inflation

Greetings from Palmia Observatory

Well, this week we start off with a rocket launch viewing opportunity and a chance to try out the Nikon P1000 superzoom camera on the Moon and Jupiter.  Also we will review some aspects of how the idea of the big bang and inflation are turned into a scientific hypothesis and how predictions made by that hypothesis can then be verified or rejected based on observations.



The SpaceX Falcon 9 lifted off from Vandenberg on Wednesday at 7:17AM.  I listened to the livestream event, while out on a walk with the Astronomer Assistants, Ruby and Danny, and looked for any rocket exhaust and couldn't see anything in the sky.  This photo was taken in the direction of Vandenberg just after the livestream announcement that the booster was already on its way back to the landing zone.  Darn, I had hoped to be able to see something, especially when the clouds sort of contributed to mostly clear skies.  We know that some of the rocket launches are visible from south OC.  The recent blog post of October 8, 2018 described the details of how several OC Astronomers were able to view an earlier SpaceX launch from the Vandenberg viewing site, while Resident Astronomer Peggy photographed the nighttime launch from south OC.  If you want you can easily check out those details at: http://www.palmiaobservatory.com/2018/10/hooray-experienced-successful-spacex.html.  Did anybody else have better photo success?

Hmm, no SpaceX Falcon 9 exhaust seen in south OC at 7:24AM (Source: Palmia Observatory)
Hmm, no SpaceX Falcon 9 exhaust seen in south OC at 7:24AM (Source: Palmia Observatory)


So, we couldn't see anything of the rocket launch, but the clouds behaved all day and into the early night.  As part of the continuing evaluation of the Nikon P1000 superzoom camera, we were able to take the image below showing the waxing moon.  Wow, the detail looks pretty good!  The camera focal length was zoomed just far enough that the moon's full image was in the camera frame.
Full frame Nikon P1000 image of the moon with focal length near maximum (Source: Palmia Observatory)
Full frame Nikon P1000 image of the moon with focal length near maximum (Source: Palmia Observatory)

Also since Jupiter was still so bright and no clouds in the way, yet, let's see what Jupiter looks like in the superzoom.  Recall, that in the previous post, we used the 600mm telephoto lens to capture the moons of Jupiter while getting an overexposed image of Jupiter.  This time I used the superzoom feature to try to get an image of Jupiter that is not overexposed.

Hmm, this image is not what was expected.  No bands are visible and the image is very grainy.  The image of Jupiter is found to be just 70 pixels in diameter.
Underexposed, 1/5 full frame Nikon P1000, max focal length image of Jupiter (Source: Palmia Observatory)
Underexposed, 1/5 full frame Nikon P1000, max focal length image of Jupiter (Source: Palmia Observatory)

So what was going on and is this the best that can be expected with the superzoom camera?  It turns out that I was way underexposing the images of both the Moon and Jupiter.  Check out this screenshot of the moon's image in Photoshop and the histogram of the image.  So, yes, Photoshop allows you to stretch the image and recover pretty good detail as seen in the previous image of the Moon, but it also means that the original camera image was way underexposed.  I could have easily increased the exposure time by probably 5 times and sill not saturated the image.  Too bad, I didn't realize this condition while out in the field where I could have rectified the situation.  But by then, the clouds had come back in and Jupiter faded below visibility.  Darn!  So, it is not clear if the limited detail is due to the limitations of the camera or just the exposure setting.  If the exposure time were way just 5x or 10x longer for the Jupiter image, it might have been able to see more detail, maybe even a band or two, but we won't know because the recognition came too late and now we are forecast for clouds this next week.
Histogram of underexposed Nikon P1000 image of the moon (Source: Palmia Observatory)
Histogram of underexposed Nikon P1000 image of the moon (Source: Palmia Observatory)


Ok, with the clouds out and about, we have time to make some more comments about Hartlefest and some of the study that I have been putting in following what was learned there.  First up though is that the group photo of the folks attending the 80th birthday celebration for Jim Hartle has been released.  Here you see Jim Hartle in the front next to Kip Thorne and I am in the back row behind Sean and Kip.  Again, I hadn't really recognized or appreciated the impact that Jim Hartle had on the developments in cosmology until Hartlefest and now, as much as I enjoy his clear and understandable textbook on general relativity, can only say, thanks for everything and congratulations, Jim Hartle!
Group photo at Hartlefest, June 7, 2019 at UCSB KITP (Source: Robert Bernstein)
Group photo at Hartlefest, June 7, 2019 at UCSB KITP (Source: Robert Bernstein)


Ok, so let's return to some of the lessons learned or study opportunities spawned by Hartlefest and consider how the big bang idea, once it was defined carefully enough, led to measurements and paradoxes that suggested that the idea was not correct as formulated and needed to be updated.  When the first measurements of the CMB indicated its thermal black body distribution which was isotropic across the sky, the big bang theory got a big boost in popularity.  But the idea of the singularity, which is anathema in physics, had to be updated and one approach what we have just seen is the No Boundary Proposal.  Another great idea, which also updates and improves the story of the big bang is the idea of inflation.  Inflation solves major problems with the big bang story including the horizon problem, the flatness problem, the entropy problem and the primordial perturbation problem, but there is no evidence of how inflation started or how it ended.  Some versions of the story say that inflation never ended and the universe keeps inflating and creating the multiverse.  So, even though this is just a story, and no observational evidence exists just yet, the predictive nature of the story has proven to be very productive and observation predictions and tests have been developed.

As part of my continuing study of the inflation story, I dusted off a copy of "Introduction to the Theory of the Early Universe", which my friends at Amazon tell me I purchased way back in December 2011.  Hmm, as I recall when I first got the book, I found it way to difficult to work through, but now, almost 8 years later, it might be the right time!

Fantastic book on Cosmological Perturbations and Inflationary Theory by Gorbunov and Rubakov
Fantastic book on Cosmological Perturbations and Inflationary Theory by Gorbunov and Rubakov


We have time here to consider just one of the big bang problems: the horizon problem.  The illustration below shows the situation where the observable patch of sky, that we could observe today, would have a history of being causally disconnected from close by regions.  We would be measuring from the apex point of the upper time cone and yet, temperature measured from out location shows all of those regions having the same thermal characteristics.  This would be highly unlikely so the astronomers making the measurements, although convinced by the blackbody nature of their measurements that this could be from the big bang, that something was not quite right in their understanding of how this could have come about.

Illustration of the horizon problem were observable patches were not in causal contact (Source: D. Gorbonov & V. Rubakov, "Intro to the theory of the early universe")
Illustration of the horizon problem were observable patches were not in causal contact (Source: D. Gorbonov & V. Rubakov)

Then when the concept of inflation showed up and solved this problem and the other problems as well, everyone was quite happy.  You can see in the illustration below that the supposed inflation started at the apex of the bottom cone, which then caused the sky regions we observe today to have the same causally connected thermal blackbody spectrum that is observed at the apex of the upper cone.  So the big bang occurred after the effects of inflation had occurred.



Illustration of how inflation solves the horizon problem (Source: D. Gorbonuv & V. Rubakov)

The textbook goes into more of the details and describes how to calculate the sizes of the regions and thermal properties of each region.  So most everyone is happy with inflation in that it offers a solution to the major problems associated with the big bang story.  But the story of inflation has its own problems in that no one knows how inflation started and how it ends.  The good news is that the inflation story generates many testable predictions, so we are able to find the best inflation story that is not ruled out by the observational evidence.  The textbook has many other chapters covering topics like how various theories of inflation cause both scalar and tensor perturbations in the CMB and that these predictions can be ruled in or ruled out by measurements.  So we see how the stories that astronomers tell are eventually turned into scientific proposals, which make predictions, and then observations are used to tell which is the best story.  Yes, the story telling goes on and now with the advent of more accurate measurements of the CMB and of large scale structure and now even gravitational wave astronomy, many of the inflation stories will be ruled out and the best story will then maybe go on to be finally confirmed by observational evidence and win the Nobel Prize!



Until next time,

Resident Astronomer George



If you are interested in things astronomical or in astrophysics and cosmology
Check out this blog at www.palmiaobservatory.com


No comments:

Post a Comment