Heidi B. Hammel
Series 2 Episode 4
The Wonder of the Stars with Dr. Heidi B. Hammel
Series 2 Episode 4
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Welcome to What’s Your Map?
Have you ever seen a shooting star? Did you know that there are different stars in the sky during winter and summer? In this episode, Dr Heidi B. Hammel takes Jerry on a jaunt around the constellations, and talks to him about the cutting edge of space exploration.
Heidi is an interdisciplinary scientist at NASA and Vice President of Science at the Association of Universities for Research in Astronomy (AURA). In her role at AURA, Heidi works with some of the world’s most famous telescopes such as Hubble and the James Webb Space Telescope (JWST). She studies planetary systems and the origins of life, seeking signs of life on other planets. Heidi and her colleagues also watch the skies for possible interplanetary collisions, keeping our Earth safe.
The Norton’s Star Atlas is over 100 years old. Containing 16 maps of different slices of the sky, it was created by the British schoolmaster, Arthur Philip Norton - and ignited a young Heidi’s passion for astronomy. Heidi deciphers Map 5 of the atlas for Jerry, picking out familiar constellations, and explaining how even such an old map can still be used to navigate the stars.
She also talks about leading the Hubble team that studied the impact of a comet on Jupiter in 1994, the development of telescope technology, and how she and her colleagues predict extinction level threats. And now… look up!
To zoom in to a high-definition image of the map during the podcast, click on the image below:
Map 5 and 6 from Norton's Star Atlas and Reference Handbook (1973). Credit: Private collector's own.
Norton’s Star Atlas and Reference Handbook is a manual on how to observe the northern and southern skies and is illustrated with a set of 16 celestial charts. It was created in 1910 by British school teacher Arthur Philip Norton (1876-1955). The Atlas is currently in its 20th edition!
Norton's Star Atlas title page. Credit: Private collectors own.
The Star Atlas became highly popular and a great many professional and amateur astronomers ‘cut their teeth’ using Norton’s because of its accessible language and layout. It included celestial maps drawn on a projection specially designed by Norton himself!
Image Credit: Private collector's own
The night sky is divided into six vertical segments, or gores, just as they would be on a terrestrial globe. Each gore uses a grid system; right ascension (the cosmic equivalent of longitude) indicated by roman numerals, and declination (the cosmic equivalent of latitude). The northern and southern skies are depicted on separate polar hemisphere charts on a standard azimuthal equidistant projection.
This chart, Map 5 in the Star Atlas, shows many constellations including Orion, Taurus, Aries, Perseus, Cetus, Lepus, and Andromeda, with dashed outlines to delineate the limits of each constellation as if state boundaries. The position and magnitude, or brightness, of each star is illustrated, and explained by a handy key in the lower left of the map. A green/blue colour has been used to highlight the Milky Way. Heidi explains that it is described as such due to the milky-cloud appearance it has as a cluster of millions of stars, which the Romans called 'galactea' meaning “milk spilled”.
Throughout history, humans have looked up to the stars to make sense of the Earth, and as a handy tool to navigate by. Hailing from all over the world, the earliest 'astronomers' were known as 'cosmographers'. Their legacy is held in the naming of the stars, and the imagery given to the constellations. As Heidi and Jerry mention, it doesn't just hail back to the Greco-Roman tradition, but also from the ancient civilisations in the Middle East, giving the example of the brightest star in Taurus, Aldebaran. The first documentation of systematic astronomical observations date back to the Assyro-Babylonians, circa 1000 BCE.
The constellation, Orion (centre), from Cellarius' Chart of the Constellations of the Southern Hemisphere
One of the finest early star atlases is Andreas Cellarius’ landmark “Harmonia Macrocosmica” (1661). A handsome example of this atlas is held in the The Sunderland Collection.
A luxuriously embellished work, the atlas features twenty-nine sumptuous Baroque-style charts of the night sky and solar system. It was published during a time when classical cosmologies by figures such as Claudius Ptolemy were being challenged by new emerging theories by polymaths Nicolaus Copernicus and Tycho Brahe.
Nowadays, astronomers don't rely on almanacs and manual telescopes alone; a wealth of enhanced technology has been developed to assist them to continuously observe, track, and photograph celestial phenomena. Over Heidi's career, she has seen this advancement first hand...
Photo credit: NASA Hubble Space Telescope. NASA ID: PIA18165. Public Domain.
The Hubble Space Telescope was launched into low Earth orbit in 1990. It is one of the largest and most versatile telescopes ever created and an important research tool. NASA state that it "has changed our fundamental understanding of the universe".
The Hubble telescope is named after American astronomer and pioneer of observational cosmology, Edwin Hubble (1889-1953).
Two Comet Shoemaker-Levy 9 Impact Sites on Jupiter (18 July 1994). Credit: NASA, H. Hammel and MIT.
Blasts created by the impacts of comet Shoemaker-Levy 9 fragments left Jupiter with a "bruised" appearance (22 July 1994). Credit: NASA and the Hubble Space Telescope Comet Team.
In 1994, Heidi led the Hubble Space Telescope Team that studied the impact of Comet Shoemaker-Levy 9 when it collided with the planet Jupiter. They discovered a comet during observations of Jupiter and used the Hubble Telescope to track the orbit of the comet to the point where they could predict an interplanetary impact - what Heidi describes as a “biosphere changing event”.
Credit: NASA. NASA ID: GSFC_20171208_Archive_e000162. Public domain.
The James Webb Space Telescope, launched in December 2021, is the largest, most powerful and most complex telescope in the world. It is equipped with high-resolution and high-sensitivity instruments, allowing it to capture objects too old or distant for the Hubble Telescope. It enables scientists and astronomers to study things such as the formation of the first galaxies, and the atmosphere surrounding potentially habitable exoplanets, and so much more!
It is named after James Edwin Webb (1906-1992), an American government official who served as the second Administrator of NASA from 1961 to 1968 - during the almighty Apollo Programme. Among his accolades, he was a hugely important proponent for the development of space telescopes.
As well as looking up into the night sky, Heidi suggests that we should look out for future advancements in research and technology in the space sector and in particular, the Habitable Worlds Observatory Telescope and data from studies on Dark Energy.
Credit: Pixabay
About Dr. Heidi Hammel
Dr. Heidi B. Hammel is an Interdisciplinary Scientist on NASA’s James Webb Telescope Project and Vice President for Science at AURA (Association of Universities for Research in Astronomy). AURA is a non-profit consortium of universities and institutions that manages and operates astronomical facilities, including the Hubble Space Telescope and James Webb Space Telescope.
As a planetary astronomer, she has studied our Solar System's outer planets, and their rings and moons, with the Gemini, Hubble, Keck, Spitzer, and other telescopes. She studies biosphere changing events, cosmic collisions, and "protects our species from the universe" by studying other planets.
Her latest research involves studies of Uranus and Neptune with Hubble and other Earth-based observatories. She's an expert on these distant planets, and she was a member of the Imaging Science Team for the Voyager 2 encounter with Neptune in 1989. Hammel has been part of a team working to launch a mission to the outer solar system sometime in the next decade. In 2020, she was awarded the Masursky Award of the American Astronomical Society's Division for Planetary Sciences (AAS/DPS) for her service to the planetary science community.
She received her undergraduate degree from the Massachusetts Institute of Technology (MIT) in 1982 and her Ph.D. in physics and astronomy from the University of Hawaii in 1988. After a post-doctoral position at NASA's Jet Propulsion Laboratory, Pasadena, Calif., Hammel returned to MIT, where she spent nearly nine years as a Principal Research Scientist in the Department of Earth, Atmospheric, and Planetary Sciences. She received the 1996 Urey Prize from the American Astronomical Society for her outstanding achievement in planetary science. She joined Space Science Institute in 1998, and retains a position there as a Senior Research Scientist.
Hammel is an award-winning communicator of science, having a unique ability to communicate of a range of levels from kindergarten to post-graduate-school nearly simultaneously. She is especially skilled at translating complex science concepts into easy-to-understand language for general audiences. She also has a strong belief in the value of public education, and believes it is one of the most important things a scientist can do. Hammel won the AAS/DPS 2002 Sagan Medal for her outstanding communication by an active planetary scientist to the general public, as well as the Public Understanding of Science award from the Exploratorium in San Francisco, California.
Her biography "Beyond Jupiter: The Story of Planetary Astronomer Heidi Hammel" has been published by the National Academy of Sciences as part of the series "Women's Adventures in Science." She was profiled in Newsweek Magazine in 2007.
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