September 20, 2023
From Princeton to the Edge of the Universe in Six Short Steps
Michael Strauss
Professor of Astrophysical Sciences; Chair, Department of Astrophysical Sciences, Princeton University
From Princeton to the Edge of the Universe in Six Short Steps
Michael Strauss
Professor of Astrophysical Sciences; Chair, Department of Astrophysical Sciences, Princeton University
Introducer: George Bustin/ Speaker: Michael Strauss
Minutes of the Third Meeting of the 82nd Year
John Cotton opened the third meeting of our 82nd year at 10:15 AM on Sept. 20, 2023, to 115 guests. Julia Coale led the invocation. Abbreviated Minutes of our meeting of Sept. 13 were prepared by Ann Schmidt and read by Rob Cogan. Four guests were welcomed: Harold Kaskin, Joe Battat, Eric Van Marke, Lyra Sato.
John Cotton reminded us of dues payments, elections next week, and the availability of Covid boosters.
Old Guard thumb drives for new members and those who wish to exchange old ones for updated ones are available. There is a $5 charge if you have lost yours and want a new one.
Our speaker at our next meeting, September 27, will be Janis Napoli, Director of Horticulture, Grounds for Sculpture. Her topic will be “The Evolving Landscape of Grounds for Sculpture.”
George Bustin introduced our speaker, Professor Michael Strauss, whose talk was entitled “From Princeton to the Cosmic Microwave Background in Six Short Steps.”
Professor Strauss started at Princeton as assistant professor in 1994 and rose through the ranks to his present position of Chair, Department of Astrophysical Science and Professor of Astrophysical Sciences.
He earned his B.A. in Astronomy and Physics in 1984 at UC Berkeley and his Ph.D. in Physics, also at UC Berkeley. From 1991 to 1995, he was Long-term Member of the Institute for Advance Study. From 1989 to 1991, he was Norris Fellow, at Caltech.
Professor Michael Strauss used the library lecture hall to help us visualize the enormous distances across space and into deep space. He began with comparing the distance of the longest commercial airline trip, NYC to Singapore, with the circumference of the Earth. The flight is about 19 hours for a distance of 40% of the Earth’s circumference. This distance is nothing compared to the distance to our sun, which is 150,000,000 km from Earth or 1 AU. As the numbers get larger, the unit of light years is used for measuring distance.
The six short steps:
1. With Earth’s orbit at the scale of the lecture hall, the Earth is the size of a sand grain (actually, kitty litter), and the Sun, in the center, is the size of an apple. The average distance of Pluto from the Sun is 39.5 AU; that of Jupiter from the Sun is 5.2 AU.
Light travels 300,000 km in one second, so sunlight takes 8 light minutes to reach Earth. Pluto is 5 light hours from the Sun, or 39.5 AU’s.
2. With our nearest star (Proxima Centauri) at the edge of the room there are 4.3 light years from it to our Sun. The Sun, in the center of the room, is in the center of our solar system. The solar system is now scaled down to the size of a grain of sand.
3. Again we need to rescale the lecture hall. In the center, the solar system is the size of a grain of sand, and the Milky Way Galaxy, of which we are a part, is 100,000 light years across.
The Milky Way galaxy is something we can see.
Now we need to again recalibrate our lecture hall to imagine the rest of the Universe.
4. The Milky Way, dish-sized at the new scale, is in the center of our room and the Andromeda galaxy, also dish-sized, is at the edge of the room, 2.5 million light years away. Andromeda galaxy is the brightest galaxy visible in our night sky. It is the most distant thing we humans can see with the unaided eye, before light pollution or on a trip to the desert southwest (e.g., New Mexico) or Chile.
5. With the Sloan Great Wall in the room, the Andromeda and Milky Way galaxies are separated by the length of a paper clip. The Sloan Great Wall, seen in the new James Webb telescope, contains thousands of galaxies and is 1.4 light years long.
6. Finally, the whole observable universe is 85 billion light years across. In this rescaled room, the Sloan Great Wall is the length of a pencil.
In all of space, there are billions and billions of galaxies, like the Andromeda or Milky Way galaxies. These galaxies, reduced to the size of single stars, float around space like fish in a pond, singly and in schools. Remember, our Milky Way galaxy is only 100,000 light years across. The distance to the edge of the Universe is, thus, 85,000 times what we can see across the Milky Way.
Numerous gems were imbedded in Professor Strauss’s talk and in responses to audience questions:
A fly-by image of Pluto shows reality in terms of tectonic plates and volcanoes on its surface. Reality checks the imagination of astronomers.
Io, a moon of Jupiter, is covered with many active volcanos.
One can see the formation of stars in the Eagle Nebula, which is 4 light years across.
The universe we can see is 13.8 billion years old. It was produced in the “Big Bang.” That’s another subject!
Dark matter and dark energy were discussed as unknowns. Professor Strauss will personally hand over a Nobel Prize to anyone who can figure out what either is.
The Nishimura comet is currently flying through our solar system. Look for it when it stops raining.
Respectfully submitted,
Lincoln S. Hollister
John Cotton opened the third meeting of our 82nd year at 10:15 AM on Sept. 20, 2023, to 115 guests. Julia Coale led the invocation. Abbreviated Minutes of our meeting of Sept. 13 were prepared by Ann Schmidt and read by Rob Cogan. Four guests were welcomed: Harold Kaskin, Joe Battat, Eric Van Marke, Lyra Sato.
John Cotton reminded us of dues payments, elections next week, and the availability of Covid boosters.
Old Guard thumb drives for new members and those who wish to exchange old ones for updated ones are available. There is a $5 charge if you have lost yours and want a new one.
Our speaker at our next meeting, September 27, will be Janis Napoli, Director of Horticulture, Grounds for Sculpture. Her topic will be “The Evolving Landscape of Grounds for Sculpture.”
George Bustin introduced our speaker, Professor Michael Strauss, whose talk was entitled “From Princeton to the Cosmic Microwave Background in Six Short Steps.”
Professor Strauss started at Princeton as assistant professor in 1994 and rose through the ranks to his present position of Chair, Department of Astrophysical Science and Professor of Astrophysical Sciences.
He earned his B.A. in Astronomy and Physics in 1984 at UC Berkeley and his Ph.D. in Physics, also at UC Berkeley. From 1991 to 1995, he was Long-term Member of the Institute for Advance Study. From 1989 to 1991, he was Norris Fellow, at Caltech.
Professor Michael Strauss used the library lecture hall to help us visualize the enormous distances across space and into deep space. He began with comparing the distance of the longest commercial airline trip, NYC to Singapore, with the circumference of the Earth. The flight is about 19 hours for a distance of 40% of the Earth’s circumference. This distance is nothing compared to the distance to our sun, which is 150,000,000 km from Earth or 1 AU. As the numbers get larger, the unit of light years is used for measuring distance.
The six short steps:
1. With Earth’s orbit at the scale of the lecture hall, the Earth is the size of a sand grain (actually, kitty litter), and the Sun, in the center, is the size of an apple. The average distance of Pluto from the Sun is 39.5 AU; that of Jupiter from the Sun is 5.2 AU.
Light travels 300,000 km in one second, so sunlight takes 8 light minutes to reach Earth. Pluto is 5 light hours from the Sun, or 39.5 AU’s.
2. With our nearest star (Proxima Centauri) at the edge of the room there are 4.3 light years from it to our Sun. The Sun, in the center of the room, is in the center of our solar system. The solar system is now scaled down to the size of a grain of sand.
3. Again we need to rescale the lecture hall. In the center, the solar system is the size of a grain of sand, and the Milky Way Galaxy, of which we are a part, is 100,000 light years across.
The Milky Way galaxy is something we can see.
Now we need to again recalibrate our lecture hall to imagine the rest of the Universe.
4. The Milky Way, dish-sized at the new scale, is in the center of our room and the Andromeda galaxy, also dish-sized, is at the edge of the room, 2.5 million light years away. Andromeda galaxy is the brightest galaxy visible in our night sky. It is the most distant thing we humans can see with the unaided eye, before light pollution or on a trip to the desert southwest (e.g., New Mexico) or Chile.
5. With the Sloan Great Wall in the room, the Andromeda and Milky Way galaxies are separated by the length of a paper clip. The Sloan Great Wall, seen in the new James Webb telescope, contains thousands of galaxies and is 1.4 light years long.
6. Finally, the whole observable universe is 85 billion light years across. In this rescaled room, the Sloan Great Wall is the length of a pencil.
In all of space, there are billions and billions of galaxies, like the Andromeda or Milky Way galaxies. These galaxies, reduced to the size of single stars, float around space like fish in a pond, singly and in schools. Remember, our Milky Way galaxy is only 100,000 light years across. The distance to the edge of the Universe is, thus, 85,000 times what we can see across the Milky Way.
Numerous gems were imbedded in Professor Strauss’s talk and in responses to audience questions:
A fly-by image of Pluto shows reality in terms of tectonic plates and volcanoes on its surface. Reality checks the imagination of astronomers.
Io, a moon of Jupiter, is covered with many active volcanos.
One can see the formation of stars in the Eagle Nebula, which is 4 light years across.
The universe we can see is 13.8 billion years old. It was produced in the “Big Bang.” That’s another subject!
Dark matter and dark energy were discussed as unknowns. Professor Strauss will personally hand over a Nobel Prize to anyone who can figure out what either is.
The Nishimura comet is currently flying through our solar system. Look for it when it stops raining.
Respectfully submitted,
Lincoln S. Hollister