ESCI final lecture 24

Finding Worlds

Radial Velocity • Transit Photometry • Microlensing

Radial Velocity

The radial velocity method relies on the fact that a star does not remain completely stationary when it is orbited by a planet. It moves, ever so slightly, in a small circle or ellipse, responding to the gravitational tug of its smaller companion. When viewed from a distance, these slight movements affect the star's normal light spectrum, or color signature. If the star is moving towards the observer, then its spectrum would appear slightly shifted towards the blue; if it is moving away, it will be shifted towards the red

Transit Photometry

This method detects distant planets by measuring the minute dimming of a star as an orbiting planet passes between it and the Earth. The passage of a planet between a star and the Earth is called a "transit." If such a dimming is detected at regular intervals and lasts a fixed length of time, then it is very probable that a planet is orbiting the star and passing in front of it once every orbital period.

Microlensing

Microlensing is the only known method capable of discovering planets at truly great distances from the Earth. Whereas radial velocity searches look for planets in our immediate galactic neighborhood, up to 100 light years from Earth, and transit photometry can potentially detect planets at a distance of hundreds of light-years, microlensing can find planets orbiting stars near the center of the galaxy, thousands of light-years away

What are the ethics?

Several prominent NASA scientists argue we must first determine if any life exists on a planet before we overrun it with Earthlings…

Sagan Series

The long astronomical perspective

Traditional Sci-Fi: Terraforming Futures

(e.g., classic space colonization narratives) •Planets are modified to become Earth-like •Humans act as engineers of entire ecosystems •Technology is used to: • thicken atmospheres • warm cold planets • introduce Earth species •Nature is something to be re-designed for human needs •Assumes expansion + control of environments is possible and desirable

Becky Chambers’ Vision: Ecological Coexistence

(Becky Chambers) •Planets are treated as already complete ecosystems •Emphasis on observation, respect, and non-interference •Humans adapt to environments rather than changing them •Focus on: • environmental ethics • cultural diversity • humility in exploration •In works like To Be Taught, If Fortunate, terraforming is avoided entirely Core idea: “We learn to live within worlds, not remake them.”

Ursula K. Le Guin: Cultural & Ecological Balance

Ursula K. Le Guin •Focuses on societies as ecosystems of meaning and culture •Worlds are shaped by social choices as much as environments •Often explores: • limits of power and empire • sustainable societies • gender, politics, and environment as interconnected systems •In works like The Dispossessed and The Word for World is Forest, exploitation of nature mirrors exploitation of people “Worlds are shaped by how societies organize power, culture, and environment together.”

Sagan Series

The Frontier is Everywhere

Issues with finding another planet and terraforming

Expense • Sociological extremes • Medical and Health issues • Ecology • Travel across vast distances • Resilience

Terraform asteroids

• Hard to do due to low gravity • Parraterraforming- make enclosure around an asteriod. Use it for some aspect of structure, minerals, tunneling, protection, and gravity.

Set off nuclear explosions

“Eventually you could transform Mars into an Earth-like planet,” he said on The Late Show (video is viewable from the U.S. only), adding that there were two ways to do this. “The fast way is drop thermonuclear weapons over the poles,” he said, leading Colbert to brand him a supervillain. “Superman doesn’t say we’ll drop thermonuclear bombs, that’s Lex Luthor!” said the host

Live in space

Schismatrix Plus (1996) Complete ShapersMechanists Universe by Bruce Sterling • Lots of sci-fi explore this • Going to really be difficult

So why is our planet so important?

Resources limited • Networked world, cascading breakdowns • Technology – diminishing return • Technology – can have catastrophic consequences • Time of perils

Humanity will endure?

We are a blip on the time scale of the diverse life history of planet Earth • We have the potential to change, adapt, modify, and diversify both our planet, our culture, and ourselves

big pciture questions

How are climate problems we are battling today linked with societal choices beginning in the 19th and 20th century ? 2. How have scientists observed/reconstructed these changes? 3. Why is there sea level rise? What ideas are out there to think about making storms more vigorous? 4. What are some 21st century solutions to adapt to these deep-rooted Earth System blips? 5. What are some 21st century engineering solutions to improve our chances at coping and minimizing future climate change?

Copyright Tamiko Thiel- American theoretical physicist known for his work in quantum mechanics.

•Key contributor to the development of quantum electrodynamics (QED) •Worked on the Manhattan Project during World War II Major Contributions •Helped explain how light and matter interact at the quantum level •Developed the Feynman diagrams—a visual tool for understanding particle interactions •Shared the 1965 Nobel Prize in Physics for work in QED Why he is famous beyond physics •Legendary teacher known for making complex ideas accessible •Emphasized curiosity, skepticism, and “not fooling yourself” in science •Wrote popular books like Surely You’re Joking, Mr. Feynman! Key Idea “If you think you understand quantum mechanics, you don’t understand quantum mechanics.”

Two Possible Futures for Earth

Utopian Future A world where societies successfully respond to environmental change. •Global warming is stabilized through reduced emissions and clean energy •Cities are adapted and resilient (flood protection, heat-resistant design) •Ecosystems are partially restored (reforestation, ocean recovery, biodiversity protection) •Food, water, and energy systems are sustainable and widely accessible •Climate cooperation reduces inequality between regions Climate change is managed and impacts are minimized through adaptation and mitigation.

Dystopian Future A world where environmental change is poorly managed or ignored. •Global temperatures rise significantly, increasing extreme heat, droughts, and storms •Sea-level rise displaces coastal populations and reshapes cities •Ecosystems collapse in many regions, with major biodiversity loss •Resource scarcity leads to conflict, migration, and inequality •Climate impacts disproportionately affect vulnerable populations Climate change drives instability and forces reactive, uneven adaptation