Cosmic String Discovery Candidate

• Astronomers found evidence for cosmic string using Planck satellite data
• Cosmic strings: hypothetical giant threads of pure energy, longer than galaxy, zero thickness
• Originally proposed 1970s as topological defects from early universe plasma
• Ruled out 1990s due to cosmic microwave background observations
• Revived by string theorists - tiny strings could grow to huge proportions
• Act as strong gravitational lens, duplicate images cleanly (one left, one right around string)
• Identification method: look for galaxies appearing twice without visible lensing cause
• Follow-up observations at Himan Chandra telescope
• One candidate shows almost perfect duplication
• Spectral analysis: both image parts have almost identical spectra
• Caveat: nearby galaxies plausibly made of similar star stuff
• Previous false positive: 2006 Hubble telescope double dot turned out to be galaxy pair

Mercury's Continuing Shrinkage

• Mercury undergoing global contraction - becoming wrinkly like old apple
• Lost few kilometers in diameter over past few billion years
• First suspected 1970s from Mariner 10 Mission images showing wrinkled surface
• Confirmed 2015 by Messenger Mission data
• Shrinkage causes unclear: rapid cooling or spin slowdown
• Surface covered in graben (downward dips) and horsts (upward counterparts)
• Graben relatively young (less than 300 million years)
• Age determination: older graben would be covered by sediments and rubble
• Conclusion: Mercury hasn't stopped shrinking
• ESA spacecraft mission to Mercury planned 2025

Nuclear Clock Breakthrough

• German-US researchers built clock with record accuracy: 1 second in 300 billion years
• Used big x-ray laser
• Current atomic clocks use cesium atoms: 1 second in 300 million years accuracy
• Nuclear resonances advantages over electron resonances:
  • Much higher energies = smaller wavelength = higher precision
  • Less susceptible to environmental disturbances
• Focus on scandium (atomic number 21) nucleus
• Incredibly narrow resonance structure makes very accurate pacemaker
• Measured scandium nuclear resonance with unprecedented precision
• Accuracy 1,000 times better than current atomic clocks
• Roughly 3 femtoseconds per second precision
• Challenge: nuclear resonances require higher frequency x-ray lasers
• European group also working on thorium-based nuclear clock
• Applications: navigation, space travel, timekeeping accuracy

First Quantum Engine

• Japanese-German collaboration built first quantum engine
• Exploits difference between bosons and fermions
• Fermions don't like sharing same space (electrons in atomic shells)
• Bosons find it cozy to sit in same place
• Entire atoms have similar properties based on electron shell filling
• Can combine two fermions to make boson
• Used ultra-cold gas of ~60,000 lithium atoms (initially fermions, spaced out)
• Applied magnetic field to coerce fermions to combine into bosons (moved closer)
• Relaxed field - atoms become fermions again
• Converted magnetic field energy to mechanical energy
• Similar to car engines: inject fuel, ignite, expand, push piston
• Quantum engine expansion comes from boson-to-fermion transition
• Works at temperatures near absolute zero
• Won't move cars anytime soon

Human Disease Simulator Device

• Lunchbox-sized device called "LICE" built by Northwestern University
• Alternative to conventional in-vitro technologies
• 8 interconnected wells containing organic tissue or bacteria
• Connected by pumps and channels transporting artificial blood/liquids
• Simulates interactions between tissue in various body parts
• Already studying polycystic ovarian syndrome origins
• Hope for popularity in physiology and pathology laboratories

Spinning Black Holes and New Physics

• Headlines about Kerr black holes (spinning black holes) finding new physics
• Named after New Zealand physicist Roy Kerr
• Almost all black holes rotate due to angular momentum conservation
• Focus specifically on extremal Kerr black holes (maximal theoretical rotation speed)
• Extremal black holes don't exist in real universe
• Paper estimates quantum gravity effects near extremal/near-extremal black holes
• Effects would be noticeable and measurable if such objects existed
• Author admits didn't check the mathematics

AI for Alien Life Detection

• AI joining search for extraterrestrial life
• Differentiates biological from non-biological samples
• Trained on 130+ samples pre-labeled by human scientists
• 90% accuracy in judging other samples
• Correctly identifies recent biological traces (shells, teeth, rice)
• Also identifies ancient biological samples (coal, oil, amber)
• Organic molecules degrade over time - identifying old samples challenging
• Proposed use: analyzing ancient sediments, including Mars samples
• Currently only for sediment analysis

Photonic Computing Advancement

• Chinese scientists simplified photonic computing method
• Saves space and energy
• Works by shooting laser light through microscopic optical components
• Light routed with mirrors and beam splitters for different calculations
• Especially useful for matrix multiplication
• Matrices represented by grid of tiny interferometers
• Very energy/time efficient vs normal computers
• Challenge: photonic computers generally encode complex-valued matrices
• Photons carry path and phase information
• Most applications only need real numbers, not complex
• New method simplifies photonic matrix multiplication for real numbers
• Smartly removed components, reduced chip size, improved energy efficiency
• Part of trend toward specialized hardware for specific calculations