Podcaster: Loretta Cannon for the AAS-HAD
Title: H’ad astra historia Ep 203 – Interstellar, Part 1
Organization: Historical Astronomy Division
Link: https://had.aas.org/
Description: Today’s guest: Dr. Jamie Rankin, Voyager Deputy Project Scientist, talks with us today about all things Interstellar. She is also an Associate Research Scholar and Lecturer in Space Physics at Princeton University. NASA-JPL continues to communicate with both Voyagers 1 and 2 as they explore interstellar space. Closer to home, IBEX and three soon-to-be-launched new spacecraft study the protective bubble of our star system from the inside, while also investigating our star’s ever-changing effect on Earth.
H’ad astra historia is the official podcast for the Historical Astronomy Division of the American Astronomical Society. We’re here to share stories from and about the people who study the stars, planets, and the cosmos. We’ll be hearing from individuals who not only study the history of astronomy, but also those who lived it, who were “in the room” during pivotal events within the last 50 years or so.
podcast music: “Frost Waltz” Kevin MacLeod (incompetech.com), licensed under creative commons: by attribution 4.0 license (http://creativecommons.org/licenses/by/4.0/)
Bio: Loretta Cannon (an AAS affiliate via Rose City Astronomers) is a science-and-word-nerd who really likes the stars. She quite enjoys working as HAD’s podcaster, bringing astronomy stories to you.
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Transcript:
Rather than provide a complete transcript, we’re sharing links for further reading for the topics or names you’ve heard in today’s episode: “Interstellar Part 1”.
Dr. Jamie S. Rankin: https://spacephysics.princeton.edu/people/jamie-s-rankin-phd
Dr. Rankin’s PhD thesis: https://thesis.library.caltech.edu/11168/
Telescope Array Project (Univ of UT): http://www.telescopearray.org/
Dr. Edward C. Stone: https://www.caltech.edu/about/news/edward-stone-1936-2024
and https://en.wikipedia.org/wiki/Edward_C._Stone
Voyager Mission Status: https://science.nasa.gov/mission/voyager/where-are-voyager-1-and-voyager-2-now/
This page has a table with (in real time) elapsed mission time and the distance each spacecraft has traveled (distance from Earth or the Sun). During the Spring (around March-ish), the distance from Earth decreases for a bit before increasing again; this is normal because the Earth orbits the Sun annually. Farther down on the webpage is a Table listing all instruments on the two spacecraft, including dates when an instrument was turned off or stopped working.
Archimedean Parker Spiral: https://en.wikipedia.org/wiki/Heliospheric_current_sheet
and see diagram from article in Journal of Space Weather & Space Climate:
https://www.swsc-journal.org/articles/swsc/full_html/2021/01/swsc190081/F1.html
and this fun site: https://demonstrations.wolfram.com/TheInterplanetaryMagneticFieldParkerSpiral/
Coronal Mass Ejections: https://www.swpc.noaa.gov/phenomena/coronal-mass-ejections
and https://earthsky.org/sun/is-a-solar-flare-the-same-thing-as-a-cme/
NASA-JPL’s video ‘ringing of space’: https://www.youtube.com/watch?v=LIAZWb9_si4
with this descriptive text: “NASA’s Voyager 1 spacecraft captured these sounds of interstellar space. Voyager 1’s plasma wave instrument detected the vibrations of dense interstellar plasma, or ionized gas, from October to November 2012 and April to May 2013.
The graphic shows the frequency of the waves, which indicate the density of the plasma. Colors indicate the intensity of the waves, or how ‘loud’ they are. Red indicates the loudest waves and blue indicates the weakest.
The soundtrack reproduces the amplitude and frequency of the plasma waves as ‘heard’ by Voyager 1. The waves detected by the instrument antennas can be simply amplified and played through a speaker. These frequencies are within the range heard by human ears.
Scientists noticed that each occurrence involved a rising tone. The dashed line indicates that the rising tones follow the same slope. This means a continuously increasing density.
When scientists extrapolated this line even further back in time (not shown), they deduced that Voyager 1 first encountered interstellar plasma in August 2012.
The Voyager spacecraft were built and continue to be operated by NASA’s Jet Propulsion Laboratory, in Pasadena, Calif. Caltech manages JPL for NASA. The Voyager missions are a part of NASA’s Heliophysics System Observatory, sponsored by the Heliophysics Division of the Science Mission Directorate at NASA Headquarters in Washington.
Credit: NASA/JPL-Caltech/University of Iowa”
SciTechDaily article on Voyager’s Sounds of Interstellar Space (May 2021):
https://scitechdaily.com/hear-the-eerie-sounds-of-interstellar-space-captured-by-nasas-voyager/
Prof Don Gurnett’s Selected Sounds of Space: https://space.physics.uiowa.edu/plasma-wave/space-audio/sounds/
He worked on Voyager and co-authored the Sept 2013 Science article on Voyager 1’s crossing the heliopause.
Science Comic (the running joke) How Many Times Voyager 1 had Left the Solar System:
https://xkcd.com/1189/
JPL article (Sept 2013) on Voyager 1’s crossing (w/excellent though-not-to-scale-graphic):
https://www.jpl.nasa.gov/news/how-do-we-know-when-voyager-reaches-interstellar-space/
Official confirmation of Voyager 1’s passage into Interstellar Space (Science Sept 2013):
https://www.science.org/doi/10.1126/science.341.6151.1158
Johns Hopkins Univ article – Voyager 1 reaches interstellar space (Oct 2013):
https://hub.jhu.edu/gazette/2013/october/news-roundup-voyager-1-leaves-solar-system/
Continuing saga of Voyager 1’s magnetic field readings (Feb 2019):
https://pubs.aip.org/physicstoday/online/30645/The-confounding-magnetic-readings-of-Voyager-1
NASA-JPL Teachable Moment article on Voyager 2 reaching interstellar space:
https://www.jpl.nasa.gov/edu/resources/teachable-moment/then-there-were-two-voyager-2-reaches-interstellar-space/
NASA has a wealth of webpages for teachers to use that contain “standards-aligned lessons and related activities to get students doing math and science with a real-world (and space!) connection.”
There’s a graphic in this article that shows a nice comparison (between Voyager 1 and Voyager 2) of low-energy particles and magnetic field behavior at the heliopause crossing (see p. 4 of the pdf): https://iopscience.iop.org/article/10.1088/1742-6 (and there’s a test to prove you’re human before you’re redirected to the article)
MIT Space Plasma Group site contains a wealth of Voyager 2 data:
https://web.mit.edu/space/www/voyager/voyager.html
Commercial website with weird or ‘dimpled’ graphic of heliosphere boundary near Voyager 2’s crossing (caution: 3rd party cookies on site):
https://www.dreamstime.com/astronomical-illustration-position-solar-system-probes-pioneer-voyager-objects-leaving-solar-image165022047
NASA-JPL article on the Voyagers’ interstellar trajectories depicts the heliosphere as an oblate spheroid, and includes the two non-communicating interstellar Pioneer space probes (June 2012): https://www.jpl.nasa.gov/infographics/voyager-interstellar-trajectory/
Article comparing Voyager 2’s Exit from Solar System to Voyager 1’s, and depicts a bullet-shaped heliosphere (Nov 2019):
https://www.scientificamerican.com/article/voyager-2-makes-an-unexpectedly-clean-break-from-the-solar-system/
IBEX (NASA mission site): https://science.nasa.gov/mission/ibex/
includes a youtube video of IBEX discoveries
NASA article on IBEX ribbon (Feb 2016): https://www.nasa.gov/missions/ibex/nasas-ibex-observations-pin-down-interstellar-magnetic-field/
includes graphic of ribbon (a narrow region of energetic neutral atoms)
Princeton Univ’s IBEX site: https://ibex.princeton.edu/
includes information on the IBEX Education & Public Outreach Program!
and see https://www.princeton.edu/news/2020/06/11/nasas-ibex-charts-11-years-change-boundary-interstellar-space
NASA: Studying the Edge of the Sun’s Magnetic Bubble (Oct 2021):
https://www.nasa.gov/missions/ibex/studying-the-edge-of-the-suns-magnetic-bubble/
excellent article that defines terms, discusses Voyagers and IBEX, and includes great graphics
IMAP (Princeton website): https://imap.princeton.edu/
IMAP Updates: https://imap.princeton.edu/news/mission-updates
IMAP Instagram: https://www.instagram.com/imapspacemission/
IMAP facebook: https://www.facebook.com/IMAPSpaceMission
NASA’s Voyager HOME page: https://science.nasa.gov/mission/voyager
Voyager Mission Overview: https://science.nasa.gov/mission/voyager/mission-overview/
Voyager as seen in NASA’s Eyes on the Solar System:
https://eyes.nasa.gov/apps/solar-system/#/sc_voyager_1
This page is a real treat! You can ‘see’ the spacecraft’s location in real time, or you can move it backwards to watch its travels since 1977, and so much more.
podcast music: “Frost Waltz” Kevin MacLeod (incompetech.com), licensed under creative commons: by attribution 4.0 license (http://creativecommons.org/licenses/by/4.0/)
End of podcast:
365 Days of Astronomy
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