麻豆传媒

KARAWANG, WEST JAVA, INDONESIA, JAN-18 : An employee shows newly-launched Rupiah banknotes which are illuminated by the ultraviolet in Indonesian Money Printing Public Company (Peruri), Karawang, West Java On January 18, 2017. There are elements of security that can readily be known to the public and there will only be known specialist. (Photo by Dasril Roszandi/Anadolu Agency/Getty Images)

This week鈥檚 new questions

What makes certain materials glow under UV light, and not others? And why do our own farts smell OK, whereas those of other people鈥檚 smell awful?

Humans

At your fingertips: The nail art that opens doors to the metaverse

Tom Gauld ticks umpteen things off the 2022 to-do list

Twisteddoodles: Welcome to the Centre for Human Research

Planktonium photo series about the unseen world of living microscopic plankton Planktonic trochophore stage of the larva of a polychaete worm Photo Jan van IJken

Life

Mesmerising photos reveal the microscopic beauty of plankton

The Triangulum Galaxy, a.k.a., Messier 33, is a spiral galaxy about 3 million light years from Earth. It belongs to the Local Group of galaxies that includes the Milky Way and Andromeda galaxies. Chandra's X-ray data (pink) reveal a diverse range of objects including neutron stars and black holes that are pulling material from a companion star, and supernova remnants. An optical image from the Subaru telescope in Hawaii (red, green, and blue) shows the majestic arms of this spiral galaxy that in many ways is a cousin to our own Milky Way.

Space

Find the most distant galaxy visible to the naked eye

Humans

Do all Australian critters glow green under UV light, or is it borax?

Spectacled flying fox (Pteropus conspicillatus) baby or bub is cared for by Claudia Barton, volunteer wildlife carer at Tolga Bat Hospital, North Queensland, Australia October 2012

Why do we have five digits on each hand, and not some other number?

When does a theory become a fact and who decides?

HKC9W5 Dnepropetrovsk, Ukraine - August 23, 2015: Armed forces salute with guns during ceremony of raising Ukrainian national flag

Can bullets fired in the air cause injury when they return? (part 2)

It is common in many countries for people to fire guns upwards in celebration, and sometimes the returning bullets can wreak havoc, say our readers

This week鈥檚 new questions

Twisteddoodles: The Christmas argument that won鈥檛 die easy

Environment

Volcanic disaster settles a blanket of ash across La Palma

Humans

Zero-gravity beds and flame-grilled 鈥渢ruth鈥�: The 2021 Feedback awards