Science & Nature
1439 sites
Subcategories:
- Astronomy & Space (396)
- Chemistry (8)
- Earth Sciences (26)
- Biology (79)
- Physics (30)
- Mathematics (59)
- Weather & Climate (104)
- Amateur Radio (682)
- Electronics (47)
https://mathcs.clarku.edu/%7Edjoyce/hilbert/toc.html
Created by David E. Joyce of Clark University, this site presents the full text of David Hilbert's famous 1900 lecture outlining 23 unsolved mathematical problems that shaped 20th-century mathematics. Each problem links to its own dedicated page with references to key solutions and related works, making it an invaluable reference for anyone studying the history and foundations of mathematics.
http://smartsonline.org/
SMARTS is the Southwest Metro Amateur Radio Transmitting Society, a ham radio club serving members who are licensed or pursuing their FCC Part 97 amateur radio license. The club hosts weekly nets on the WB0RMK repeater, monthly meetings, and community breakfasts, making it a welcoming hub for both new and experienced ham radio operators.
http://nefariousplots.com/figures/4
An interactive data visualization called 'The Population of Space' charts every human spaceflight from Yuri Gagarin in 1961 through 2014, grouping missions by launch vehicle and coloring them by historical era. Created in honor of the 45th anniversary of Apollo 11, it offers a fascinating way to explore how long humans have spent in space, which nations sent them, and how the shift from Soviet stations to the International Space Station shaped our continuous presence off-world.
http://thehellhole.com/
A detailed German-language educational site covering black holes and singularities, exploring topics from stellar and supermassive black holes to Hawking radiation, mathematical models, and even the theoretical dangers of black holes at CERN. The site draws a fascinating parallel between modern astrophysics and Norse mythology's concept of the Maelstrom, making complex science accessible through storytelling.
https://muircom.com/6meters.htm
A reference page by Alan Muir (VE7BEU) documenting 6-meter amateur radio frequencies in the 50-54 MHz band, including repeater pairs used in British Columbia and Washington State. It covers transmitter offsets and CTCSS tones, compiled on behalf of the Westcoast Amateur Radio Association in Victoria for submission to the BC Amateur Radio Coordination Council.
nsml.org
NEW!
https://nsml.org/
The North Suburban Math League (NSML) organizes competitive math meets for Chicago-area high schools, with five competitions held throughout the school year. The site provides contest archives, meet schedules, written and oral topic lists, coach resources, and a history of NSML alumni who have earned medals at the International Mathematical Olympiad.
https://sagan.diletante.net/
A fanlisting dedicated to the beloved astronomer and science communicator Carl Sagan, gathering fans from around the world who admire his work and legacy. Built and maintained by a fan known as C.:., the site includes information about Sagan, membership listings, and links to related resources.
https://sarts.org.sg/
The Singapore Amateur Radio Transmitting Society (SARTS) is the national organization for ham radio enthusiasts in Singapore, offering resources on licensing, frequency bands, and getting started with amateur radio. The site features news posts on topics like FreeDV signals, web SDRs, and satellite launches, along with a marketplace, gallery, and membership information for the local ham community.
https://tgale.home.xs4all.nl/valves.html
Trevor Gale's comprehensive reference site covers vintage vacuum tubes and valves, offering pinout data, characteristics lists, military-to-commercial conversion tables, repair hints, substitution guides, and circuit diagrams for old receivers and amplifiers. Maintained as a companion to the rec.antiques.radio+phono newsgroup FAQ, it serves as a practical technical resource for both seasoned restorers and newcomers to valve/tube circuitry.
https://ncatlab.org/nlab/show/HomePage
The nLab is a collaborative wiki covering advanced mathematics, physics, and philosophy with a strong emphasis on category theory, homotopy theory, topos theory, and their connections to theoretical physics. It serves as an encyclopedic reference for researchers and students working at the intersection of higher mathematics and mathematical physics, offering thousands of deeply interlinked articles.