Tag Archives: space

Misnomers: Dr. Srinivasan on Mostly Neutron Stars

It took me a year and an email to understand how merging neutron stars could generate heavy elements.  For this you need protons and from where do these protons come.  The year was for intermittent research and the email due to failing in that research.  As it happens, neutron stars are chock full of particulate goodness, far more than their name implies.   On the one hand it is good to know how it works, on the other hand it shows that my research skills could use some improvement.

Dr. G. Srinivasan, Researcher Emeritus from the Raman Research Institute explains the beaks and gizzards of these dense objects in great detail.   His 12 part lecture series “A Random Walk in Astrophysics” is also available.

Youtube Channel: International Centre for Theoretical Sciences

Where are they now?: Carol Meier on Voyagers 1 and 2

Narrator Carol Meier has a meticulously researched, splendidly detailed, and wonderfully delivered update on the twin Voyager spacecraft and their epic journey of discovery from Pasadena to the outskirts of the solar system.  It isn’t clear if this is a commissioned piece or one she did on spec.  It is engrossing either way.

Youtube Channel: Carol Meier

Calling the shot: Brian Metzger on kilonovae

Soon after LIGO‘s first detection of a black hole-black hole merger, the astronomical community was hinting about a potentially more scientifically  exciting event within the interferometer’s grasp: The merging of two neutron stars. When two dark objects coalesce, the product is unsurprisingly dark. Colliding neutron stars on the other hand might emit light of some kind and the collision product need not necessarily be a black hole. More intriguingly, so-called kilonovae resulting from neutron star collisions have been proposed as the actual origin in our universe of many elements heavier than iron, challenging the conventional wisdom of these coming from supernovae.

Here’s a prescient talk by Prof. Brian Metzger of Columbia University and coiner of the term ‘kilonova’ on the consequences of neutron star binary mergers. He discusses their signatures in the gravitational wave record and across the electromagnetic spectrum to their ultimate role in nuclear synthesis. Given at Harvard on 16 March 2017, it is quite accessible for a technical colloquium presentation. A mere five months later on 17 August 2017, LIGO and its European counterpart VIRGO indeed detected the merger of two neutron stars and set of a flurry of observational activity across the globe and in space which confirmed at least qualitatively the predictions by Metzger and his group.

The details are still confusing.  For example, we can assume that it takes a long time for two neutron stars to form, presumably from the death as a supernova of each of a large, but not too large, binary pair.  These violent events will eject a lot of material into the interstellar medium.  The neutron stars then spiral slowly and combine, releasing a lot of neutrons to stick to light elements, transmuting them up the periodic table through the r-process.  But, where do these light elements come from if the ejecta from each of the progenitor stars has had a very long time to spread? (*)

Harvard’s Edo Berger has a concise summary of the multimessenger gold rush incited by the event in a special issue of Astrophysical Journal Letters.  Many of the papers are free to download.  As an aside, I was acquainted with Edo when he was an undergraduate physics student at UCLA while I was a researcher in the same department.  I had no idea then he’d become one of the Dukes of Earl of  high energy astrophysics.

(*) Addendum 20 April 2019: After a year of futility in not finding an answer to this question, I emailed Prof. Metzger and asked.  In a prompt and gracious reply he said that the ejecta from the merging neutron stars create the seed nuclei required for the r-process.  There are sufficient protons (10-30%) in the ejecta to form nuclei of mass number ~100 within milliseconds.  These then absorb further neutrons within the constraints of beta decay to create very heavy elements within a few seconds.  So,  it seems that neutron stars aren’t neutrons all the way down!

30 May 2020: New video source; prior channel was deleted.

Youtube Channel: CfA Colloquium

 

Youtube Channel: Kowch737

 

Lyrical Gangsta: Nature on Tom Lehrer

Tom Lehrer at 90: a life of scientific satire

Andrew Robinson celebrates the high notes in the mathematician’s inimitable musical oeuvre.
Lehrer agrees with mathematician Stanislaw Ulam (one of the builders of the atomic bomb) that rhyming “forces novel associations … and becomes a sort of automatic mechanism of originality”. As he told me in 2008: “If ‘von Braun’ didn’t happen to rhyme with ‘down’ (and a few other words), the most quoted couplet in the song would not exist, and in all probability the song itself would not have been written.”

Closer to home, Nancy Keystone‘s ‘Apollo’ trilogy cast sharp, cynical, brilliant eyes on whitewashing Nazi rocket scientists into America’s space program.

Vimeo Channel: Nancy Keystone

 

Space Music: Paul Novros accompanies the universe

The documentaries below were made in the 1970s by Lester Novros, then a professor at the USC film school where his students included George Lucas.  The understated elegance of these films is nicely framed by Paul Novros‘s music.  The younger Novros is a professor of jazz at CalArts.  I asked him whether he had any soundtracks available.  He was pleasantly surprised to be reminded of the work but has no separate recordings or scores.

Lester Novros and his Graphic Films studio had a major albeit little-known influence on Stanley Kubrick and 2001: A Space Odyssey. Special effects legend Douglas Trumbull worked with him in Los Angeles but ultimately moved to work directly with Kubrick in England. Barbara Miller’s article “Graphic Films and the Inception of 2001: A Space Odyssey” is good reading.

via the U.S. National Archives Youtube Channel

via the Department of Defense channel at the Internet Archive

via the National Archives and Records Administration at the Internet Archive

(links to videos 2 and 3 updated 3/22/19 following the deletion of Jeff Quitney’s Youtube Channel)

Monolith Monograph: The Making of 2001: A Space Odyssey

A young filmmaker dives deeply in five parts into the technical and artistic innards of his (and one of my) favorite movies. One wishes that he spoke a little slower and left some breathing room in his edits but it is an earnest, meticulous, and illuminating effort. The engineering alone that went into 2001 is awe-inspiring. Did Kubrick sleep during the two years it took to make?

Via Channel CinemaTyler

Fly US to the Moon: von Braun vs. Houbolt

To this day, the questionable Wernher von Braun gets credit for most American space accomplishments of the 1950s and 1960s. He tirelessly aimed at the stars (with the occasional drops on London) but engineering realities were at odds with his grandiose plans and even grandioser rockets. John Houbolt’s Lunar Orbit Rendezvous approach eventually won out and his role in Apollo’s success is insufficiently known. Here’s a comparison.

Youtube Channel: Dan Beaumont Space Museum

Youtube Channel: The A/V Geeks
(Link updated 3/22/19 following the deletion of Jeff Quitney’s Youtube Channel)

The Deep Space Network – Helping Voyager phone home

The Voyager Spacecraft – Image courtesy NASA and JPL

It is now official, humankind has put its toe into interstellar space as Voyager 1 crossed into the heliopause nearly a year ago. This milestone has been hotly debated in the scientific literature as heavyweight teams presented evidence pro and con. It was only in the last few weeks, however, all parties have agreed on what the data from the probe mean. And they agree that it is now past the interface between the solar wind and the great beyond.
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