How Not to Control the Weather for Your Dog

I’m rooting around in my bag for a pen, and pull out a laser pointer by mistake. Since I’d really prefer not to be grading, I flip it on and shine it on the floor next to the spot where Emmy is half-dozing. She immediately leaps up (she’s pretty spry for a dog of 12…), […]

Nobel Prize for Blue LEDs

The 2014 Nobel Prize in Physics has been awarded to Isamu Akasaki, Hiroshi Amano and Shuji Nakamura for the development of blue LED’s. As always, this is kind of fascinating to watch evolve in the social media sphere, because as a genuinely unexpected big science story, journalists don’t have pre-written articles based on an early […]

Yes Virginia, There Are Quantum Jumps

In a weird coincidence, shortly after I wrote a post about “quantum leap” as a metaphor, I was looking up some stuff about John Bell and ran into mentions of a paper he wrote called “Are There Quantum Jumps?” Bell is borrowing a title from Schrödinger, who wrote a pair of articles (really, one article […]

Finding Extrasolar Planets with Lasers

On Twitter Sunday morning, the National Society of Black Physicsts account retweeted this: Using Lasers to Lock Down #Exoplanet Hunting #Space — ✨The Solar System✨ (@The_SolarSystem) September 28, 2014 I recognized the title as a likely reference to the use of optical frequency combs as calibration sources for spectrometry, which is awesome stuff. Unfortunately, […]

Son of Interstellar Laser Communications

I didn’t plan to do a follow-up to yesterday’s post about the optics of sending messages with lasers, but then I starting idly thinking about detection, prompted in part by a bunch of conversations with my summer students about single-photon detectors. which led to scribbling on the back of an envelope, which led to Googling, […]

Interstellar Laser Communications

In the comments to yesterday’s grumpy post about the Fermi paradox, makeinu raises the idea that advanced aliens would be using more targeted communications than we do: On the point about electromagnetic communications: even we are now using lasers to target communications with space, because it’s simply more efficient and reliable. It’s also basically impossible […]

Laser-Cooled Atoms: Cesium

Element: Cesium (Cs) Atomic Number: 55 Mass: One stable isotope, mass 133 amu. Laser cooling wavelength: 854nm, but see below. Doppler cooling limit: 125 μK. Chemical classification: Yet another alkali metal, column I of the periodic table. This one isn’t greyish, though! It’s kind of gold color. Still explodes violently in water, though. Other properties […]

Laser-Cooled Atoms: Chromium

Element: Chromium (Cr) Atomic Number: 24 Mass: Four “stable” isotopes between 50 and 54 amu. Chromium-50 is technically radioactive, with a half-life considerably longer than the age of the universe, so… Laser cooling wavelength: 425nm, but see below. Doppler cooling limit: 120 μK. Chemical classification: Transition metal, smack in the middle of the periodic table. […]

Laser-Cooled Atoms: Lithium

Element: Lithium (Li) Atomic Number: 3 Mass: Two stable isotopes, masses 6 and 7 amu Laser cooling wavelength: 671 nm Doppler cooling limit: 140 μK. Chemical classification: Alkali metal, column I in the periodic table. Yet another greyish metal. We’re almost done with alkalis, I promise. Less reactive than any of the others, so the […]