Universe
Why is space so dark even though the Universe is filled with stars?
This age old question has been dubbed Olbers’ paradox. Credit: John Colosimo/ESO “Why is space so dark even though the Universe is filled with stars?” — Nikhil, age 15, New Dehli People have been asking why space is dark despite being filled with stars for so long that this question has a special name – …
What is the smallest thing in the Universe?
“What is the smallest thing in the Universe that actually exists?” — Mimi, age 12, Abeokuta, Nigeria To find an answer, we asked physicist Omololu Akin-Ojo, who teaches this subject. A physicist is someone who studies physics. Physics is the science of energy, forces and particles. We study physics in order to be able to …
How do atoms – the building blocks of everything – form?
“How do atoms form?” — Joshua, age 7, Shoreview, Minnesota R ichard Feynman, a famous theoretical physicist who won the Nobel Prize, said that if he could pass on only one piece of scientific information to future generations, it would be that all things are made of atoms. Understanding how atoms form is a fundamental …
2026 is poised to be an exciting year for space exploration
In 2026, astronauts will travel around the Moon for the first time since the Apollo era, powerful new space telescopes will prepare to survey billions of galaxies, and multiple nations will launch missions aimed at finding habitable worlds, water on the Moon and clues to how our solar system formed. Together, these launches will mark …
What is below Earth, since space is present in every direction?
“What is below Earth, since space is present in ever direction?” — Purvi, age 17, India If you’ve seen illustrations or models of the solar system, maybe you noticed that all the planets orbit the Sun in more or less the same plane, traveling in the same direction. But what is above and below that …
How are dark matter and antimatter different?
“What is dark matter and what is antimatter? Are they the same or different?” — Namrata, age 13, Ghaziabad, India Imagine an epic video game with your favorite hero as a character. Another character is a mirror-image twin who shows up occasionally, exploding everything they touch. And, to add an extra level of difficulty, the …
Why isn’t there any sound in space?
“How far can sound travel through space, since it’s so empty? Is there an echo in space?” — Jasmine, age 14, Everson, Washington In space, no one can hear you scream. You may have heard this saying. It’s the tagline from the famous 1979 science fiction movie “Alien.” It’s a scary thought, but is it …
What is the universe expanding into if it’s already infinite?
“What is the universe expanding into if it’s already infinite?” — Mael, age 10, Missoula, Montana When you bake a loaf of bread or a batch of muffins, you put the dough into a pan. As the dough bakes in the oven, it expands into the baking pan. Any chocolate chips or blueberries in the …
How could an explosive Big Bang be the birth of our universe?
“How can a Big Bang have been the start of the universe, since intense explosions destroy everything?” — Tristan S., age 8, Newark, Delaware Pretend you’re a perfectly flat chess piece in a game of chess on a perfectly flat and humongous chessboard. One day you look around and ask: How did I get here? …
What is space made of? Explaining the components from radiation to dark matter
“What is space made of – what does gravity actually bend?” — Phil, age 12, Birmingham What comes to mind when you think of space? Imagine a friend boasting about a spacious building, stadium or museum they recently visited. Do you envision the building as vast and expansive? Is it simply very large, or does …