If you want to keep something safe, build a mountain fortress above the Arctic Circle. That’s the thinking behind the Svalbard Global Seed Vault. Almost every nation keeps collections of native seeds so local crops can be replanted in case of an agricultural disaster. The Global Seed Vault, opened in 2008 on the far-northern Norwegian island of Spitsbergen, is a backup for the backups. It’s badly needed as many as half the seed banks in developing countries are at risk from natural disasters or general instability. The vault can hold up to 4.5 million samples, which will be kept dry at about 0°F (-18°C). Even if the facility loses power, the Arctic climate should keep the seeds viable for thousands of years.
Grains of sand come in all shapes and sizes, but the most common size is about a half millimeter across. You could put 20 grains of sand packed in side-by-side to make a centimeter, 400 grains would make one square centimeter, and 8,000 grains could fit into one cubic centimeter. By extension, this means that an astounding 1,888,000 grains of sand would fit into a single cup - which is definitely more than I would have guessed.
If our sun and all the other stars in our universe were the size of a grain of sand, all the stars in our galaxy would fill an Olympic-sized swimming pool.
If our galaxy were a grain of sand, the galaxies would fill several olympic-sized swimming pools.
We know there are 100 to 400 billion stars in the Milky Way and more than 100 billion galaxies in the Universe — maybe as many as 500 billion. If you multiply stars by galaxies, at the low end, you get 10 billion billion stars, or 10 sextillion stars in the Universe. At the high end, it’s 200 sextillion.