What is Astronomy: Definition and 820 Discussions

Astronomy (from Greek: ἀστρονομία, literally meaning the science that studies the laws of the stars) is a natural science that studies celestial objects and phenomena. It uses mathematics, physics, and chemistry in order to explain their origin and evolution. Objects of interest include planets, moons, stars, nebulae, galaxies, and comets. Relevant phenomena include supernova explosions, gamma ray bursts, quasars, blazars, pulsars, and cosmic microwave background radiation. More generally, astronomy studies everything that originates outside Earth's atmosphere. Cosmology is a branch of astronomy that studies the universe as a whole.Astronomy is one of the oldest natural sciences. The early civilizations in recorded history made methodical observations of the night sky. These include the Babylonians, Greeks, Indians, Egyptians, Chinese, Maya, and many ancient indigenous peoples of the Americas. In the past, astronomy included disciplines as diverse as astrometry, celestial navigation, observational astronomy, and the making of calendars. Nowadays, professional astronomy is often said to be the same as astrophysics.Professional astronomy is split into observational and theoretical branches. Observational astronomy is focused on acquiring data from observations of astronomical objects. This data is then analyzed using basic principles of physics. Theoretical astronomy is oriented toward the development of computer or analytical models to describe astronomical objects and phenomena. These two fields complement each other. Theoretical astronomy seeks to explain observational results and observations are used to confirm theoretical results.
Astronomy is one of the few sciences in which amateurs play an active role. This is especially true for the discovery and observation of transient events. Amateur astronomers have helped with many important discoveries, such as finding new comets.

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  1. L

    Is it possible to major in just astronomy

    , or would you be majoring in physics if you want to study astronomy? Say for example you want to study astronomy, if you go to assist.org, there is no articulation agreement for earning a degree in astronomy? Ok, if you look here there is no school in California, at least, offering any degree...
  2. R

    What formulas do I need to solve the above problems?

    I was going to put this up in the homework forum, but I feel the folks down here are more capable of helping me out. I have to do an assignment, but I cannot go in for office hours to get help from my professor. Regretfully, I lost the sheet and forgot to grab another until just a few days...
  3. M

    Astronomy Question: Maximum latitude

    1. Taking the latitude of Dublin as 53.3 degrees North, and the tilt of the Earth's axis and the lunar orbit to be 23.5 and 5 degrees respectively, what is the maximum altitude of the Moon as seen from Dublin? What is the maximum altitude as seen from the North pole? 2. Homework Equations...
  4. M

    Programs Should I try and get a second degree in astronomy?

    So I'm currently a junior at the University of Maryland majoring in Criminal Justice/Criminology. I've been pretty interested in astronomy for a few years, but lacked the focus to really feel confident in such an undertaking. I have no idea now what specifically I'd like to do with an additional...
  5. S

    Redshift first year astronomy

    redshift ""first year astronomy"" how do i find distance using redshift? please keep in mind that this is first year astronomy course i am currently taking having some trouble doing it. don't know where to start
  6. B

    Need Help Answering Astronomy Questions? Download the PDF!

    I have four questions that need to be answered. They are from my university course that I am taking in general astronomy 2. Could anybody tell me how I would obtain the detailed solutions to arrive at the answers? I have attached a pdf file of the questions and answers, please download it and...
  7. E

    Developed an interest in, Astronomy? Astrophysics?

    I've recently been reading articles (primarily wikipedia) about different plants, their sizes, and all elements required in the identification of certain stars, constellations etc. I'd like to learn more but simply visiting pages on Wikipedia endlessly for hours won't accumulate much aside from...
  8. P

    Solve CMB Peak Wavelength & Quark Fates | Astronomy Problem Help

    Hi, can anyone help me solve the following questions? 1.What was the peak wavelength of the CMB when R=0.5? a. What temperature does this correspond to? 2. Two quarks named Susan and Nick existed in the early universe. Susan became part of a proton and Nick became part of a neutron. What...
  9. Z

    Astronomy coursework question

    Homework Statement Assume that the vast majority of the photons in the present Universe are cosmic microwave radiation photons that are a relic of the big bang. For simplicity, also assume that all the photons have the energy corresponding to the wavelength of the peak of a 2.73K black-body...
  10. I

    Looking for online solar astronomy book/course

    Hello. I am looking for an online book or course (free) regarding solar structure/physics at the first-year graduate level. Can anyone point me in that direction? I've looked into it but haven't come up with anything very useful. Thanks in advance!
  11. T

    Astronomy and astrophysics, are they the same?

    hello all, what is the difference between ASTRONOMY and ASTROPHYSICS? thank you in advance.
  12. A

    Elementary Astronomy - Initial Mass Function

    Homework Statement Estimate the number of low and high mass stars that you expect to find in our Milky Way Galaxy now. Use the following (very approximate but about right numbers) for your estimate: The Star Formation Rate in our galaxy is approximately 1 Solar Mass per year and virtually...
  13. J

    Astronomy Reflection nebula Question

    Homework Statement 1. If you looked at the spectrum of a reflection nebula, would you see absorption lines, emission lines, or no lines? Explain your answer. As part of your explanation, describe how the spectrum demonstrates that the light was reflected from nearby stars. Homework...
  14. D

    I failed for a job in astronomy

    Yesterday I got an interview After that, they told me to try next time if this time I was not accepted and wait for their call if they want to contact. When someone told you so, does that mean you failed ?
  15. S

    Need some recommendations for books on Astrophysics and Astronomy

    I'm hoping someone can recommend a couple of good books on some varied topics. I'm looking for a good, mature series of books on the planets or even one good book covering them all. I'm also looking for interesting reads on cosmology, solar physics and galaxies. If anyone can recommend some...
  16. F

    Observing Objects at 45N 90W: Simple Astronomy Question

    Your observatory lies at a latitude of 45 N and longitude 90 W. Which object or objects can you observe from this location? An object at +87 dec, an object at -40 dec, and an object at -67 dec. I drew up a little celestial sphere for this and decided that 87 dec would be the only object I...
  17. K

    Astronomy Research for Software Engineering Student

    Astronomy Research?? Hi all, i am basically a software engineering student (pre-final year). I am good at programming and some math and physics, and i have so much craze about astronomy/space research and star gazing and everything related to astronomy. I wish i can take up some 'real'...
  18. K

    Astronomy Research: Expert Advice for Software Engineers

    Astronomy Research?? Hi all, i am basically a software engineering student (pre-final year). I am good at programming and some math and physics, and i have so much craze about astronomy/space research and star gazing and everything related to astronomy. I wish i can take up some 'real'...
  19. S

    Difference between Astrophysics and Astronomy ?

    I'm transferring schools for the fall of 2010, and one of the schools that I'm looking into offers a B.S. in Physics and a separate B.S. in Astronomy. The other school I'm looking into offers only a B.S. in Physics, though they say I can take elective courses in Astronomy. Basically, I want to...
  20. S

    Astronomy, Astrophysics, Cosmology, Planetary Science

    What exactly are the differences between Astronomy, Astrophysics, Cosmology, Planetary Science?
  21. Ivan Seeking

    Astronomy or Cosmology Christmas gift ideas

    I have a friend asking for ideas for an A or C oriented gift, including things that might be a bit of a scam, like having a star named after you. I know that you can buy land on the moon but that is expensive. Any ideas?
  22. U

    What is the formula for calculating the mass of a star in astronomy?

    Homework Statement ...Hence show that the mass of the star is M = 4\pip_{c}\left(R^{3}/3 ) Homework Equations M(r) = 4 \pip_{c}\left(r^{3}/3 - r^{4}/4R) This is the shell massThe Attempt at a Solution I already found the shell mass via intergration, and I know that I have to build up an...
  23. K

    How Do Astronomical Factors Influence Planetary Characteristics?

    okay so i was given this graph and questions and have no clue where to start! any help or tips would be great! thanks! if you can't really see the graph i have attached the actual paper with the graph so u can see it! Planet M (kg) R (km) a A (AU) MStar (kg) SStar P0(bar) T0(K)...
  24. M

    Some help with a X-Ray astronomy question please

    I've got to solve this problem and I am having quite an hard time figuring out how... Sorry, but I think I need help: "An astronomer takes a spectrum of a distant quasar using a 4m telescope. With an exposure time of one hour, the optical spectrum contains about 10,000 photons. The source...
  25. K

    Astronomy - Parallax error calculation.

    1. Homework Statement Two stars belong to the same cluster, the parallax measured to one star is (2±1)x10^-3 arcseconds, towards the other the parallax is (4±2)x10^-3 arcseconds. Find the distance to both objects seperatly and also compute the distance when both measurements are...
  26. K

    Astronomy - Parallax error calculation.

    Homework Statement Two stars belong to the same cluster, the parallax measured to one star is (2±1)x10^-3 arcseconds, towards the other the parallax is (4±2)x10^-3 arcseconds. Find the distance to both objects seperatly and also compute the distance when both measurements are combined...
  27. U

    Mass-Luminosity-Time relation (Astronomy)

    Homework Statement The lifetime of the sun on the main sequenceof the hertzprung-russel diagram is estimated to be 10^10 years. Assuming that the luminosities of stars on the upper diagram main sequence vary as mass^4, estimate the solar mass of a star for which it's main squence lifetime is...
  28. S

    Easy A Courses for Science Majors: Astronomy vs. Intro to Psychology

    whats up everyone, i am a science major, and since science courses are prerequisites, next semester i am only able to take 9 credits (gen chem 2 with lab, and precalculus) i plan on overloading with 14 credits during the summer, in order to graduate with my associates in a 2 year time period...
  29. K

    Astronomy Help: Minimum Mass of Stars & Sun's Energy Production Explained

    Hey can someone help me with the followng 2 questions, i am so confuzed and have no idea how to start and what formulas to use. 1. the minimum mass of a star is 0.08 solar mass or 80 Jupiter masses. If the fuel that powered stars was helium instead of hydrogen would the minimum mass of...
  30. R

    Explore Astronomy: Path to Becoming an Astronomer

    Hello! I wasn't sure where to post this so if I'm in error please excuse me. I find myself in a rather comfortable position of being enrolled in uni but having plenty of time to spare. Furthermore, my current academic let's me pick a major/minor next year of..well almost anything really. I've...
  31. P

    What is the Best Book for Learning About Astronomy?

    Hi, I've been looking for a good laymans book on Astronomy for ages now, but haven't been able to find one that isn't seriously heavy going on the physics front. I have plenty of astrophysics books, but not one dedicated to simple observational astronomy. Can anyone recommend a good, easy...
  32. L

    Has anyone taken an astronomy class

    what do you learn in an astronomy class, considering taking one , this is not at a university, but at a junior college. Just curious about what topics are covered.
  33. E

    What do u recoment for somwhone thats intrested in astronomy?

    what do u recoment for somwhone that's interested in astronomy?
  34. Philosophaie

    Textbook on Mathematical Astronomy

    Does anyone know a good textbook on Astronomy? Containing the elliptical quantities: a,e,i,w,N,LP,ML,MA,EA,r and v and how to convert these quantities to: RA, DEC, Azi and Elev plus more info about the planets and the stars.
  35. A

    Gap after MSc in Astronomy, will it hinder my chances of getting a PhD position?

    gap after MSc in Astronomy, will it hinder my chances of getting a PhD position?? hi all, I am an Indian student and I got my BSc in physics (Distinction) in 2006 followed by an MSc from UK in Astronomy (Merit) in 2007 (one year). I did not apply for a phd after my MSc as i thought that...
  36. P

    Help with Spectroscopy in Astronomy

    Hey everyone, Over the past few days I have been having trouble with finding research for my optics project. The topic I chose was supposed to be the physics behind how astronomer's and astrophysics measure the Spectrum of the Sun ans specifically the mathematics/physics behind the...
  37. D

    So, what are all the known paradoxs in Astronomy?

    So, what are all the known paradox's in Astronomy?
  38. P

    Astronomy vs Cosmology: Understanding the Differences Explained

    Hi all, This question may seem innocent, but I can't see a clear boundary between the two. Who could explain it please. (as short as possible).
  39. L

    How Do You Calculate Celestial Coordinates and Times in Astronomy?

    Alright, so basically, I'm freaking over this. Not littiorally, because the assignment isn't worth THAT much. But I've been working on my astronomy assignment ALL DAY. And there's some questions I can't get. I can't seem to find the answers (with reasoning) anywhere. I've tried yahoo answers...
  40. B

    Please help: astronomy questions about how earth orbits the sun

    Below are some questions. I have struggled with these questions so any help would be greatly appreciated. Thank you so much. The Earth orbits the Sun: a. in a perfect circle b.in an ellipse with the sun at the center c.in an ellipse with the sun at the focus d.in a shape...
  41. H

    Introductory Astronomy Question - function help

    The question asks to find a new expression for a function, by substituting suitable expressions for the elimination of lambda and T. The function is: b(x)= h^4 * c^3 * U(sub-lambda) / 2*(kT)^5 In this case: U(sub-lambda)= U(sub-lambda)(lambda,T) - Planck Blackbody Function x= lambda*k*T /...
  42. C

    Astronomy Logic and Accuracy: Check Your Homework with RQs and P3

    Working on a homework for a general astronomy class. Just want to make sure I'm not being inaccurate. Please let me know if I goofed something up. Thanks! RQ7: The word “apparent” in “apparent visual magnitude” is used to denote its dependence on viewing distance. These numbers refer to...
  43. G

    Astrophysics, Physics, or Astronomy

    If one's interests lie in Astrophysics, what would be the best courses to achieve a BA, MA, and then PhD in given the following circumstances: The highest level degree offered at this college/graduate school in Astrophysics is a BA, while both MA and PhD degrees are offered in both Physics...
  44. B

    Is a Career in Astronomy Worth the Time and Effort?

    would Astronomy be worth it? please help hello everybody I am 22 years old, and up until recently i was working for a well known bank as a bus./personal banker. i was making about 50k-60k a year depending on my bonuses. i just got fired a few months ago because a manager got a hold of my...
  45. planethunter

    PhD in Physics or Astronomy: Which is Better for Industry Careers?

    I am looking into a graduate program in either physics or astronomy. I plan on studying astrophysics and cosmology, but am not sure which route I should move towards- a phd in physics or phd in astronomy since I heard that if you get a phd in astronomy rather than physics it hurts your options...
  46. B

    Programs Can i go with physics and astronomy masters after doing some engineering degree

    I am a high school student. I hope to get my bachelors in physics and astronomy but i heard that there is low job opportunities for that degree (i know for PHD in physics and astronomy the story is different) And i hope to do PHD in physics and astronomy while i am doing a job(Because i have...
  47. S

    Difference between Astronomy and Cosmology is?

    What is the difference between Astronomy and Cosmology?
  48. benorin

    Works of Riemann related to Astronomy that I can understand?

    Looking for a connection to astronomy for a history of mathematics report on 19th century mathematicians. I don't do astronomy. Would like to know of any mathematical developments of Riemann that are used in astronomy that I can understand (which expressly excludes any thing with the word tensor...
  49. S

    Engineering Studying Astronomy after Engineering?

    Do you folks suppose its wise to get an Physics + Astronomy degree after engineering? Would it be a good career choice? I'm currently about to finish my first year in electronic engineering. Due to a lot of factors, I was unable to choose Astronomy when I enrolled. However, I've been...
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