Ask A Physicist

Have a physics or astronomy question? Whether you're curious about tiny, elusive neutrinos or the most massive black holes in the universe, we can help.

We are graduate students, research scientists and faculty in the Department of Physics and Astronomy at University of Delaware. We are developers of quantum computers, space weather forecasters, planet hunters and more!

Please email your question to askaphysicist@physics.udel.edu. Scroll down for information on who can ask questions and how to phrase your question.

New Questions

• Two people are on a high speed, constant velocity train on opposite ends. One person is standing on the platform. The two people aim a laser beam at the center of the train at the same time in their reference frame. In the center of the train, there is a special gun that will shoot and kill whoever's laser beam reaches it first; but if the two beams reach it at the same time it will be disarmed. Will anyone die? Will the observer see anyone die?
• What are some common naturally occurring materials that absorb infrared sunlight radiation from 1.1-2.5 microns?
• How do NASA scientists find dangerous asteroids? If they find one, what can we do about it?
• Why does Venus rotate clockwise when viewed from the North, while the other planets rotate counterclockwise?
• How much does gravity affect light? How does this relate to black holes?
• What's the percentage of habitable planets in the Galaxy? What's the current estimate of how may planets have life?
• How many planets have been found outside of the solar system?

Question Archive

• Photography
• Particles
• Plasma
• Physical chemistry
• Solar System
• Extrasolar planets
• Brown dwarfs
• Gravity
• Black holes
• Cosmology
• Neutrinos
• General relativity
• K-12 Education

Who can ask questions?

• We welcome questions from K-12 students and teachers. We ask that students put their age or grade level in the email so we can answer at the appropriate level.

• Non-scientist members of the general public may also submit questions. To help us answer at the right level, it's helpful if you add a little bit about your background -- for example, "I'm an accomplished amateur astronomer" or "I'm usually not interested in science, but I read something about climate change and I want to find out if it's true."

• College students may submit questions as long as they are not homework questions (see below). We can help with general physics concepts, but we will not compute or calculate anything for you.

• We advise journalists working on deadlines to contact individual scientists directly, rather than send questions to Ask A Physicist. The contributors to this page are volunteers, and we cannot guarantee that questions will be answered immediately.

• Professional physicists or astronomers should not use this service. We do not review manuscripts or check calculations.

How should I phrase my question?

• Make it specific enough that we can answer it in 1-2 paragraphs: "What types of nuclear reactions can produce neutrinos?" rather than "Tell me everything you know about neutrinos."

• However, if you make it too specific, you will trigger our homework question alert. Questions such as "Describe the five ways to measure the temperature of a star" or "If I throw a ball upward at 2 meters per second from a height of 1.5 meters, how high will it go?" will not be answered.

• We might not be able to help with questions that are specific to your locale, such as "What was that flash I saw in the sky at 10:00 PM last night?"