The Astrophysicist Who Caught Her Own Cancer | Dr. Becky Smethurst

TL;DR

Dr. Becky Smethurst, Oxford astrophysicist specializing in black holes, discusses her unexpected breast cancer diagnosis alongside her career studying galaxies, alien life, and the cosmos.

Key Points

• 1.Dr. Becky Smethurst is an Oxford astrophysicist with nearly 1 million YouTube subscribers. She specializes in black holes and observational astrophysics, using telescope data to study galaxies with growing supermassive black holes.
• 2.Smethurst found her own breast cancer as a fit, healthy woman in her 30s. She noticed a slight dimple on her left breast in early May the prior year, leading to a diagnosis that she described as her 'entire world just coming crashing down.'
• 3.She warns against skipping conventional cancer treatment in favor of 'natural' living. Her view is that rejecting medical treatment is gambling, and survivorship bias means people only hear from those for whom the gamble paid off.
• 4.Observational astrophysics works like population-wide cohort studies in medicine. Rather than repeating one experiment, astrophysicists observe many stars or galaxies of the same type to identify patterns, similar to how doctors track patient cohorts over time.
• 5.Scientists actively try to break their own theories rather than confirm them. Smethurst notes that headlines saying 'the Big Bang theory is wrong' are actually expected — theories are always refined as new evidence and telescope capabilities emerge.
• 6.Dark matter and dark energy make up roughly 95% of the universe and remain unexplained. Because so much of the universe doesn't interact with light, Smethurst acknowledges fundamental gaps in current astrophysical models.
• 7.The James Webb Space Telescope, launched Christmas 2021, set new distance records. It detected galaxies as far as ~13.5 billion light-years away — meaning we see them as they were when the universe was only ~300 million years old.
• 8.Stars' colors directly reveal their temperatures and life stage. Blue giant stars like Rigel are the hottest; red giants like Betelgeuse are cooler and nearing the end of their lives, expanding to conserve fuel — as the Sun will do in ~5 billion years, swelling beyond Earth's orbit.
• 9.Smethurst's emotional breakthrough came during her first professional telescope observation during her PhD in La Palma, Canary Islands. After a 20-minute exposure, a faint smudge resolved into a spiral galaxy, making her feel like a 'real astrophysicist' for the first time.
• 10.Pluto was reclassified as a dwarf planet because it hasn't cleared its orbit. Three criteria define a planet: orbiting the sun, being round due to gravity, and clearing its orbit — Pluto fails the third, also crossing Neptune's path and sharing space with other objects.
• 11.Smethurst believes life almost certainly exists elsewhere given the sheer scale of the universe. There are ~100 billion stars in the Milky Way alone, and roughly 2 trillion galaxies in the observable universe — statistically, assuming Earth is unique would be 'arrogant.'
• 12.There is currently no confirmed evidence of extraterrestrial life. Smethurst says the burden of proof is enormous, and UFOs (unidentified flying objects) can be explained by poorly understood natural phenomena like plasma balls, not necessarily alien visitors.
• 13.The search for life extends to moons like Enceladus and Titan in our own solar system. The Cassini probe detected water plumes from Enceladus; the upcoming Dragonfly mission will hop around Titan looking for life based on ammonia or methane rather than water.
• 14.Detecting biosignatures on exoplanets via the James Webb Telescope is possible but contested. The molecule dimethyl sulfide — only produced by bacteria or industry on Earth — may have been detected on planet K2-18b, but other scientists argue the same data fits a flat baseline with nothing there.
• 15.Smethurst navigated her cancer diagnosis through the UK's National Health Service. Her experience as a scientist shaped how she evaluated treatment options and misinformation, applying the same evidence-based skepticism she uses in astrophysics to her own medical care.