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Ask an Astrophysicist

Who is behind the "Ask an Astrophysicist" service?

The "Ask an Astrophysicist" service is provided by a small number of volunteers at the Astrophysics Science Division ( at NASA ('s Goddard Space Flight Center (, and is a part of the Imagine the Universe! public education/outreach site.

We do not represent the entirety of NASA. In particular, there are far better experts on human space flight and planetary explorations, two popular topics of incoming questions, elsewhere at various NASA centers.

What is our place within NASA?

NASA has its headquarters in downtown Washington, DC, and 'centers' all around the US. For example, Johnson Space Center ( in Houston, Texas, is the primary center for human space flight, Kennedy Space Center ( in Cape Canaveral, Florida, is the primary center for launch operations, and Jet Propulsion Laboratory ( in Pasadena, California is the primary center for planetary explorations. A full listing of NASA centers (, as well as news releasesfrom NASA (, are available on the web.

Goddard Space Flight Center ( in Greenbelt, Maryland (near Washington, DC) is the primary center for Earth and Space sciences. Groups within the latter study the Sun, the solar wind and the magnetosphere, as well as objects outside the solar system. Scientists in the Astrophysics Science Division ( study the universe outside the solar system using electromagnetic radiation from microwaves to gamma-rays; using cosmic-rays; and are preparing to use gravitational waves.

What questions do we answer?

As a group, our current volunteers have expertise in space-based astronomy and cosmology, particularly in in X-ray, gamma-ray, and cosmic-ray astrophysics, and of astronomy of exotic objects in general. The questions we welcome the most are the ones that we are uniquely qualified to answer: questions about the objects and processes that we observe using satellite based instruments, or in some closely related areas of astronomy or physics.

Common reasons for not answering a question

We may not answer your question if:

  1. It wasn't really a question.
  2. You entered an invalid e-mail address.
  3. It was a blatant case of "can you do my homework for me."
  4. It was completely outside our areas of expertise.
  5. You could have found the answer on our website, if you just made a little bit of effort.
  6. We ran out of time.
The last reason, unfortunately, is becoming more commonplace. Since our service relies on volunteer efforts of busy scientists, engineers, and programmers, we cannot answer all the questions we now receive. In particular, we have declared certain popular topic areas (space travel, solar system objects etc.) off-limits, since these are outside our areas of expertise.

Where else can you look for information/ask questions?

  • Search engines --- You can find a lot of information if you know how to use them effectively.
  • Learn to do a web search.
  • AskA+ locator ( of the Virtual Reference Desk can point you to various "Ask an expert" services.
  • On each subject page of our archive, we suggest a few good sites.

Imagine the Universe is a service of the High Energy Astrophysics Science Archive Research Center (HEASARC), Dr. Alan Smale (Director), within the Astrophysics Science Division (ASD) at NASA's Goddard Space Flight Center.

The Imagine Team
Acting Project Leader: Dr. Barbara Mattson
All material on this site has been created and updated between 1997-2012.

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