Short Wave Podcast Summary: "The Great Space Race ... With Clocks"

Release Date: May 26, 2025

Hosts: Emily Kwong and Regina Barber
Guest: Holly Leopardi, Atomic Physicist at NASA's Goddard Space Flight Center

1. Introduction: Time as a Navigational Tool

Emily Kwong and Regina Barber kick off the episode by drawing parallels between the historical challenges of determining longitude at sea and the contemporary hurdles faced in space exploration. They emphasize the fundamental role of precise timekeeping in navigation, both on Earth and in the vastness of space.

2. The Longitude Problem: A Historical Perspective

[00:28 - 02:17]

The hosts delve into the 1600s dilemma of calculating longitude, a critical factor for determining a ship's east-west position. Regina explains, "Longitude is like the east-west position on Earth. It's relative to the prime meridian in Greenwich, England, right?" (00:34).

Emily elaborates on the complexity of maintaining accurate time at sea:
"A ship leaving port would set two clocks, one for the prime meridian and another for local time. So crews would update their local time as they sailed, calculating it by using the position of the sun and by knowing the difference between these two times." (01:03).

Clock Drift and Its Dangers:
The rudimentary clocks of the era were susceptible to "clock drift" due to the harsh maritime environment, leading to navigational errors. Emily highlights, "Clock drift is dangerous. Regularly throughout the 16 and 1700s, this accumulation of errors threw ships so off course that it resulted in shipwrecks and lost lives." (01:32).

3. The Marine Chronometer and Its Impact

[01:58 - 02:46]

In response to the dire need for accurate timekeeping, the British government established the Board of Longitude, which initiated a contest to solve the longitude problem. The outcome was the development of the marine chronometer, a highly precise timekeeping device.

Regina summarizes the chronometer's significance:
"Fewer shipwrecks. Because now, like, ships knew the time and knowing the time let them know where they were." (02:10).

Emily adds, "This really made seafaring possible for the British Empire. So this clock changed world history." (02:17).

4. The Modern Parallel: Space Exploration and Precision Timekeeping

[02:31 - 04:29]

Drawing a connection between past maritime challenges and today's space endeavors, the hosts note that precise timekeeping is equally crucial for navigating space. Emily states, "The hurdles that were kicking around during the era of the longitude problem are repeating themselves today." (02:35).

Regina emphasizes the ambitious scope of current space missions:
"We're planning to go to Mars, maybe even further into space." (02:31).

Emily underscores the essential role of advanced clocks in space navigation:
"To navigate far from home, you need a really good clock." (02:46).

5. NASA's Quest Lab and the Development of OASIC

[04:29 - 08:17]

The narrative transitions to NASA's Goddard Space Flight Center, where the Quest Lab is at the forefront of developing next-generation atomic clocks. The hosts describe their visit, highlighting the collaborative environment of the lab.

Introducing Holly Leopardi:
Holly, an atomic physicist, explains the lab’s mission:
"The Quest Lab is like a one-stop shop for atomic physicists to do experiments and pass along those discoveries to NASA engineers, quantum engineering and sensing technologies." (04:35).

Lab Environment:
Emily and Regina provide a vivid depiction of the Quest Lab's setup, emphasizing the precision and durability required for space-bound technologies.

Renee Reynolds' Vision:
Assistant Chief for Technology, Renee Reynolds, articulates NASA's strategic direction:
"We do see quantum technology as a path to be able to move beyond some of our classical techniques that may be reaching their limits." (05:42).

6. Understanding Atomic Clocks

[08:37 - 11:37]

Emily undertakes the task of demystifying atomic clocks, likening them to intricate feedback systems. She breaks down the components:

• Oscillator:
  "Like a pendulum, which swings back and forth once per second. In modern clocks, their pendulum is actually a crystal of quartz." (09:02)

• Reference:
  "An atomic clock is called that because it uses part of an atom as its reference." (09:33)

Regina contributes by explaining atomic transitions using hydrogen as an example, making the concept accessible:
"If an atom absorbs energy... the electron will change its orbit... when the electron eventually goes down, energy is released from that atom as another photon." (09:56).

Holly introduces the OASIC (Optical Atomic Strontium Ion Clock), emphasizing its enhanced precision:
"Instead of going from shining microwave light on the atoms, we can go shine optical light or use lasers on the atoms. We can get to 10 to the minus 17, 10 to the minus 18, and even 10 to the minus 19." (11:37).

7. The Promise of OASIC and Future Implications

[11:37 - 15:09]

Enhanced Precision:
Emily explains the advantage of using optical light over microwaves, allowing for unprecedented precision that minimizes clock drift:
"The laser being precise makes the strontium atom precise, which makes the clock precise." (12:08).

Holly discusses the broader applications of these ultra-precise clocks:
"So my goal is to have a clock network in space, especially an optical clock network... you can start doing really cool fundamental physics." (13:37).

Scientific Breakthroughs:
Potential scientific advancements include:

• Monitoring Earth's gravitational field changes to track environmental shifts like melting sea ice and groundwater flow.
• Exploring the interaction between gravity and quantum mechanics, a central question in modern physics.
• Investigating dark matter interactions.

Peter Brereton reinforces the transformative power of quantum technology:
"This is the power of quantum technology, of systems that use the physics of atoms to be more accurate than systems using, like, classical physics." (12:27).

Timeline and Collaboration:
Holly outlines the project's ambitious timeline:
"The team wants a prototype system done by fall 2025, and she hopes OASIC could fly within six years." (14:33).

She also stresses the collaborative nature of the endeavor:
"It would take a lot of academics, a lot of companies, a lot of even nations to make this happen. It's bigger than just me in my lab." (14:48).

8. Conclusion

The hosts wrap up by reflecting on the significance of atomic clocks both historically and in the future of space exploration. They express admiration for the intricate science behind timekeeping and its profound impact on our understanding and navigation of the world and beyond.

Regina Barber:
"This was a great story. I loved it. I love learning about atomic clocks. Thank you for bringing it to us." (15:09)

Emily Kwong:
"It's always time for physics, Gina." (15:14)

They also give a shout-out to Deva Sobel’s book "Longitude" for listeners interested in deeper exploration of the topic.

Notable Quotes

• Regina Barber:
  "Longitude is like the east-west position on Earth. It's relative to the prime meridian in Greenwich, England, right?" (00:34)

• Emily Kwong:
  "Clock drift is dangerous. Regularly throughout the 16 and 1700s, this accumulation of errors threw ships so off course that it resulted in shipwrecks and lost lives." (01:32)

• Holly Leopardi:
  "So my goal is to have a clock network in space, especially an optical clock network... you can start doing really cool fundamental physics." (13:37)

• Emily Kwong:
  "The laser being precise makes the strontium atom precise, which makes the clock precise." (12:08)

• Regina Barber:
  "We are obsessed with acronyms." (04:58)

Key Takeaways

• Historical Significance: Accurate timekeeping was pivotal in solving the longitude problem, transforming navigation and enabling the expansion of empires.

• Modern Challenges: Space exploration demands even more precise timekeeping to navigate and conduct scientific research beyond Earth.

• Technological Advancements: NASA’s Quest Lab is spearheading the development of the OASIC, an optical atomic clock with unparalleled precision, promising significant advancements in both navigation and fundamental physics.

• Future Implications: Enhanced atomic clocks could revolutionize our understanding of the universe, from monitoring environmental changes on Earth to unraveling the mysteries of dark matter and the interplay between gravity and quantum mechanics.

Discover More:
For those intrigued by the intricate world of timekeeping and its impact on science and navigation, Deva Sobel’s book "Longitude" is highly recommended.

This summary was crafted to provide an in-depth overview of the "The Great Space Race ... With Clocks" episode of NPR's Short Wave podcast, ensuring that listeners gain a comprehensive understanding of the discussions without needing to listen to the full episode.