How Many Years in College to be an Astronomer?

Question: I am a 14 year old girl and want to be a astronomer when I get older. I was wondering how long you would have to be in college.  – Elena

Answer: Most astronomers have doctorate (PhD) degrees in astronomy or physics.  A quick tally of the number of years that it takes to get a PhD degree can be accounted as follows:

  • 4 years for your undergraduate (bachelors) degree.
  • At least 5 years, but likely not more than 7 years, to complete your graduate studies to earn your PhD degree.

You might also be interested in visiting my Careers in Astronomy section for further information on topics relevant to those interested in pursuing careers in science, and especially astronomy.

Jeff Mangum

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Equation for Orbits?

Question: Why does the following equation seem to predict stable orbits around the sun as well as for moons around planets without any involvement of balancing centripetal and gravitational forces.

The following is the equation that in my investigation seems to work for planetary motion just using geometric data.

C* Vs^2*Rs^2=Vp^2*Rp

C = 8*G^0.5 = 6.548E-5

Vs  = surface velocity of rotating sphere (i.e. sun)

Rs     = radius of rotating sphere (i.e. sun)

Vp       = orbital velocity of body orbiting the sphere (i.e. planet)

Rp       = distance of orbiting body from the center of the rotating sphere.

G = Newton’s gravitational constant

– William


Answer: I am not sure how you derived this equation, but as it is not dimensionally consistent, it does not appear to be correct.  Just checking the units of the left and right side of the equation, where Newton’s gravitational constant has units (using the cgs system) cm^3/(g*s^2):

cm^3/(g*s^2) * cm^2/s^2 * cm^2 = cm^2/s^2 * cm

cm^7/(g*s^4) = cm^3/s^2

As the units for the left and right side of the equation do not equate, your equation is not correct.


Jeff Mangum

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Why Do Stars Appear to Move in the Night Sky?

Question: Why do the stars in the sky appear to orbit? – Ariana

Answer: I think that you are asking why stars appear to move through the night sky from east to west in tracks that appear to be centered on the North Star.  These apparent star tracks are in fact not due to the stars moving, but to the rotational motion of the Earth.  As the Earth rotates with an axis that is pointed in the direction of the North Star, stars appear to move from east to west in the sky.

Jeff Mangum

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Can Black Holes Eat One Another?

Question: Ok so say the universe gets to a point where every black hole consumes everything including each other until your left with a single black hole. Or would this not be possible due to the universe ever expanding and just the vastness of the universe ? Just a thought.  – Danny

Answer: Space is actually a pretty empty place on average.  The WMAP cosmic microwave background probe measurements indicated that there are on average about 6 protons per cubic meter in the Universe.  I believe therefore that the possibility of black holes even interacting with each other is pretty small.

Jeff Mangum

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A Career in Astronomy?

Question: Hi, would you recommend someone to study astronomy from your current work experience? and why.  – Lindokuhle

Answer: I suggest that you look over the “Careers in Astronomy” posts elsewhere in this blog for some information regarding careers in astronomy.  There are many reasons to pursue a career in the sciences, and the decision to do so really rests on your personal desires and interests.

Jeff Mangum

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How to Find the Southern Cross from Panama

Question: Hello…I am visiting Panama, and live at 52degrees N in central Canada.  I heard that I should be able to see the Southern Cross from here.  At what time is best to see it, and since there is a full moon, will this affect finding it.  – Harry

Answer: I believe that you are asking how you can view the Southern Cross (in the constellation Crux) from Panama.  This time of year Crux rises in the south, just to the east of due-south point on the horizon, around 23:30 (just before midnight) and transits around 04:00 in the morning.  Crux sets around 08:00, which is an hour or so after sunrise.  As it is currently very close to a full Moon, you will not be able to avoid competing with it.

Jeff Mangum

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Do Home Wireless Routers Interfere with the Telescope Operations at Green Bank WV?

Question: Hi, I just had a general question about small, at home, wireless routers and their interference with satellite signal. I live at Snowshoe, WV, about 25 minutes away from the satellite and observatory in Green Banks, WV. Before buying a router for myself, even though friends both north, south, east, and west of me have them, I wanted to clear up any questions I had about them first and make sure that there was no way it could interfere with satellite signal.  Thank you.  – Jesse

Answer: For those readers who might not know, what you are referring to is the restrictions on radio transmitters within the National Radio Quiet Zone (NRQZ).  The NRAO Green Bank telescope facilities are within this NRQZ, which helps to limit the interference that the radio telescope facilities can experience when a man made transmitter is used near the observatory.  I believe that home wireless routers that are located many miles away from the observatory are not a source of harmful radio frequency interference to the telescope operations.  If you were to use one of these routers near the observatory, though, then the potential for them being a source of interference is much higher.

Jeff Mangum

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Questions About a Career in Astronomy

Question:  Hi, I am a freshman and am currently enrolled in an Earth Science course at my high school. We are required to interview someone involved in a field which uses knowledge of Earth Science for our final project portfolio. If you could answer these questions for me that would be great!

1. Where do you work and what is your job title?
2. What are your degree(s)?
3. How long have you been a professional in your field?
4. In your own words, what is astronomy?
5. How does the field of astronomy incorporate knowledge of earth science?
6. Describe what a career in astronomy entails — what an astronomer does.
7. Where might someone in this career be employed? (types of industry, branches of government, etc.)
8. What would be the appropriate education or training required for this career? Please include possible electives for high school as well if possible.
9. What are the advantages of becoming an astronomer? Disadvantages?
10. What are some personality traits that would be helpful in pursuing a career in astronomy? (drive, patience, etc.)
11. What’s the best tip you could give to an aspiring astronomy student?

– Sadie



  1. I am an astronomer at the National Radio Astronomy Observatory in Charlottesville Virginia.
  2. I have a Bachelor of Arts degree in Astronomy from the University of California at Berkeley and Masters of Arts and PhD degrees in Astronomy from the University of Virginia.
  3. I have been a professional astronomer since earning my PhD in 1990.
  4. The description that I can think of to describe “astronomy” is to say that astronomy is the study of how the universe works.  To be more specific, it is the study of the physical characteristics and evolution of all of the material that comprises our universe; from galaxies to dust particles.
  5. One area of astronomy that incorporates what has historically been the study of earth science is the characterization of the properties of extrasolar planets.  As we study the properties of extrasolar planets we are starting to be able to study their atmospheres and composition, which involves many of the skills involved in earth science.
  6. A career in astronomy can be quite varied in its tasks and duties.  Some astronomers work at universities or colleges and spent most of their time teaching courses and conducting research.  Others work at research facilities supporting telescope facilities and conducting research.  In general, though, the vast majority of astronomers conduct their own research and participate in education and public outreach activities.
  7. Employment in astronomy is generally either at universities or colleges or at federally-funded research facilities.  A smaller fraction of astronomers pursue careers in industry in a variety of roles that allow them to use their knowledge of physics and mathematics in support of various industrial activities.
  8. Essentially all professional astronomers have PhD degrees in astronomy, physics, or chemistry.  It is also sometimes useful for astronomers to have an understanding of the instrumentation used in our profession, so a knowledge of electronics is often useful.
  9. The main advantage of a career in astronomy is that, for the most part, we are allowed to pursue interesting scientific questions of our own design.  Most astronomers also have a fair amount of freedom to set their own work schedules.  A slight downside to a career in astronomy, and in the sciences in general, is that salaries are not commensurate with the amount of time that we spend working.
  10. Most astronomers are personally driven and inquisitive individuals.  We don’t need to be told to do most tasks as we know that tasks need to be completed in order to make progress.  I think that most astronomers take pride in the work that they do, so are highly motivated to complete their work, whether it be research, observatory support, or teaching, in the most efficient manner possible.
  11. The best tip that I could give to an aspiring high school student who is interested in astronomy is to learn as much math and science as possible.  Astronomers are basically physicists, and math is the language of physics.  A good background in physics and math is essential for a productive career in astronomy.

Jeff Mangum

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Do Gravitational Waves Need a Medium to Travel Through?

Question: Do gravitational waves need a medium to travel. Do they slow down when passing through a medium?  – Michael

Answer: Gravitational waves are best described as distortions in the fabric of space that are due to objects with mass.  These distortions can be thought of as propagating like a wave, and thus also transporting energy in the form of gravitational radiation.  This description of the wave transport of gravitational energy is very analogous to how light propagates and transports electromagnetic energy.  I believe that gravitational waves travel at the speed of light independent of the medium that they are travelling through.

Jeff Mangum

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How Fast Do Exoplanets Travel Around Their Parent Stars?

Question:  Looking at data on exoplanets, I’ve noticed a few with what seem like incredibly short projected orbital periods; single digit numbers of days per orbit.

This would seem to put these planets travelling through space at incredible velocity relative to the speed of light, at least compared to anything else in our experience.

What effects would this have, if any, on the planet – from a general relativity point of view. Would time dilation be measurable to an outside observer surveying one of these planets from up close (say, 3 or 4 AU)?  – Timothy


Answer: In fact, exoplanets travel just somewhat faster than a rocket.  An average velocity for a rocket is something like 30000 feet per second, or about 10,000 meters per second.  The velocity of an exoplanet with an orbital semimajor axis of about 0.1 AU and an orbital period of about 10 days is about 100,000 meters per second, or about 10 times that of the rocket.  Finally, the speed of light is about 300,000,000 meters per second, or about 1000 times the speed of the exoplanet.  Therefore, the space velocities of exoplanets do not appear to be fast enough to experience general relativistic effects.


Jeff Mangum

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