Discover astonishing facts about the vastness of our universe, from subatomic particles to the observable cosmic horizon. Challenge your general knowledge with five astounding questions about scale and distances in the cosmos.
What is the approximate radius of a proton, one of the fundamental particles in an atom?
Explanation: The correct answer is 0.84 femtometers, which represents the incredibly small size of a proton. 1.6 nanometers and 10 picometers overestimate the size by many orders of magnitude, and 1 micrometer is even larger and unrelated to atomic-scale particles.
How far does light travel across the diameter of the observable universe?
Explanation: The diameter of the observable universe is about 93 billion light-years, far exceeding the smaller distances listed. 300 million and 10 million light-years cover only local galactic groupings, and 1 trillion light-years is an unconfirmed and much larger estimate.
Which figure best estimates the number of stars in our galaxy, the Milky Way?
Explanation: Our Milky Way contains around 100 billion stars. 1 million and 5,000 are far too low, greatly underestimating the number. 10 trillion is much higher than current best estimates for our galaxy.
What is the speed of light in a vacuum, the fastest speed known in the universe?
Explanation: Light travels at about 299,792 kilometers per second in a vacuum. 3,000 km per second and 30,000 km per hour are much slower. 1,000,000 km per minute does not match the canonical speed recognized in scientific measurement.
What is the average distance from Earth to the Sun, known as an astronomical unit (AU)?
Explanation: One astronomical unit is about 150 million kilometers, defining the mean distance to our Sun. 384,000 kilometers is the distance to the Moon, 1.5 million kilometers is too short, and 1 billion kilometers is more than six times the actual Earth-Sun distance.