Ask A Physicist

Studies of a brown dwarf with the Kepler mission by University of Delaware Professor John Gizis have revealed evidence of a long-lasting starspot and frequent white light flares that rival the most powerful seen on the Sun. This is an artist's conception drawn by Rob Gizis.

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

Einstein's equation and time travel

• How is Einstein's equation (Gμν = 8πG Tμν) actually applied? And how does it support the theory of time travel?

Doppler Shift of Light Emitted from a Moving Thick Medium

• A light source inside a thick medium (low speed of light) is moving at a speed v towards a receiver outside in free space. What is the frequency shift of the light seen by an observer in free space?

Gravitational Quantum Tunneling

• In the same way that on a grand scale you'd need an object as massive as a black hole to distort space-time, is it possible that within a region of space at the quantum level, a particle's mass could actually be enough to create a tiny hole in which it could traverse space-time?

The Space Race

• We're doing a project on JFK and the Space Race and we could use your expertise on that topic. Did you personally hear any interesting stories about the space race program? How directly involved was JFK with NASA?

Time Dilation

• When we observe time dilation, such as on the Space Shuttle or GPS satellites, how can we be sure time is actually changing for those observers, as opposed to just the rate of matter acceleration changing?

Favorites

Extraterrestrial life

• What's the percentage of habitable planets in the Galaxy? What's the current estimate of how may planets have life?

Big Bang -> Black Hole?

• Consider our universe at the moment of the Big Bang, or perhaps a very brief moment after the initiation of the Big Bang. Wouldn't the mass density of the universe at the moment of the Big Bang have been sufficient to form/maintain a black hole rather than an explosive expansion?

Blue light and sleep deprivation

• I was recently advised to switch to red lights in the evening to help with my sleep patterns. I am told that the key is to achieve light as red as possible on the spectrum. Can this be achieved by filtering a white light through a red cover or does the light emitted have to be intrinsically red itself (eg the difference between a Christmas light with a red cover and a red heat night light for reptiles)?

Question Archive

• Light and Photography
• Particles
• Plasma
• Physical chemistry
• Solar System
• Extrasolar planets
• Brown dwarfs
• Gravity
• Black holes
• Cosmology
• Neutrinos
• Special relativity
• General relativity
• History of science
• The Space Race
• 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 are also encouraged to 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?"