QuizRiddles
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0 of 6 answered

1The green glow most often seen in the northern lights comes mainly from which gas high in the atmosphere?

2Egypt is famous for its pyramids, but which other African country has even more of them, over 200?

3Which invention was patented in 1843, more than 30 years before the telephone?

4Which metal is solid at room temperature but melts in your hand?

5The Eiffel Tower was built for the 1889 World's Fair. How long was its original permit to stand?

6The name 'googol', for 1 followed by 100 zeros, was coined in 1920 by whom?

Answer all 6 to see your result, or let the timer finish for you.

Did you know?

What makes trivia hard

Hard trivia is not about obscure dates that nobody could know. The best difficult questions have answers that feel surprising at first but make sense once explained, and they reward people who reason from what they already know. A good hard question offers plausible choices, so knowledge and logic matter more than luck. The sections below give background to the questions in this quiz, from the physics of light in the sky to the history of early inventions.

Light in the sky

Auroras form when streams of charged particles from the Sun reach Earth and are guided by its magnetic field towards the polar regions. There they collide with gases in the upper atmosphere and make them glow, much like the gas inside a fluorescent tube. Activity rises and falls with the Sun's roughly eleven-year cycle, and during strong solar storms auroras can be seen far from the poles. Similar lights have been observed on Jupiter, Saturn and other planets with magnetic fields.

Inventions ahead of their time

Many inventions appeared long before they became part of daily life. Fax machines existed decades before the telephone but remained rare until the 1980s, when cheap machines and standard phone lines made them common in offices. The first electric vehicles date from the 1830s, and electric taxis ran in London and New York in the late 1890s. Ideas often wait for supporting technology, such as better batteries, networks or cheaper materials, before they can spread.

Numbers with a story

Large numbers have long fascinated mathematicians. A googol is far bigger than the estimated number of atoms in the observable universe, which is usually put at around 10 to the power of 80. Kasner also named the googolplex, 1 followed by a googol of zeros, a number so large it could not be written out even if every atom in the universe were used as paper. Such numbers help explain the difference between very large and truly infinite.