What is Astronomy: Definition and 824 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. J

    Stellar or Solar system Astronomy?

    Stellar or Solar system Astronomy?? I'm an engineering student and next quarter I will have space for an elective class and I wanted to do something with astronomy. My options are stellar astronomy and Solar System Astronomy, my school only offers these two courses, and I don't know which one...
  2. S

    Which universities in Australia offer a PhD in Astronomy?

    Hi I am a Physics masters student from India in a college in Texas. I want to pursue a PhD in Astronomy (observational/radio) Australia. I have heard Australia is very good at obs astronomy - however google searches are revealing a lot about the telescopes and other facilities there but...
  3. S

    What universities in Australia offer a PhD in Astronomy?

    Hi I am a Physics masters student from India in a college in Texas. I want to pursue a PhD in Astronomy (observational/radio) Australia. I have heard Australia is very good at obs astronomy - however google searches are revealing a lot about the telescopes and other facilities there...
  4. astroscout

    What is the connection between hurricanes, spiral galaxies, and sunflowers?

    Nature,Astronomy and Physics have facinated me for years but I had no idea they were eerily similar in other ways. Nature produces hurricanes that in satellite photos look eerily similar to those of spiral galaxies photographed by the Hubble space telescope. Physics uses a model...
  5. N

    Can a CS Major and Astronomy Minor Lead to a Career in Space Exploration?

    One day I aspire to work in the space exploration(or something similar) field using Computer Science skills, and my knowledge in Astronomy. Is this realistic? Or would a minor in Physics be better for trying to achieve the same goal? I plan to attend the University of Utah if the makes a...
  6. E

    Available Astrophysics or Astronomy Master Scholarships

    What is the best, if not great, scholarship for a master (graduate) in Astrophysics or Astronomy? I have been looking around the internet, but I am not sure if the scholarships I have seen will allow me to study Astrophysics, and most of them have their deadlines passed. I'm also planning to...
  7. A

    Thinking about taking an astronomy or astrophysics course for fun

    Hi all, I've had an itching lately to dive into something new. Currently, I am a professional computer programmer but have always been interested in astronomy. I took an astronomy course (as well as a lab for it) when I was in college and I remember enjoying it all immensely. I want to get...
  8. M

    Going from undergrad Bio to graduate astronomy

    Hello, So I'm going to be a third year molecular and cell biology major soon and I'm barely catching up on the requirements to complete the major at my university. I really had a hard time choosing between this and physics, thinking and weighing out the differences between the two for a few...
  9. A

    What physics and math needed to start some research in astronomy

    Alright well I am in high school so my resources are limited as far as sophisticated telescope. Although I can ask around via email to see if there is any way to find time on more sophisticated technology. As far as what levels of math and physics I am at next fall I will be taking fundamentals...
  10. mishima

    High School Astronomy Class Text?

    I am a high school physics teacher looking to teach an astronomy class for juniors and seniors next year. I was wondering if there are any stand out texts for this. Thanks.
  11. N

    Coordinates and astronomy

    Homework Statement Astronomer observing the sky with a small telescope by hole at the observatory in the middle of dome (lens diameter is much smaller than the diameter of the dome). Calculate the maximum time when astronomer can still observe objects near the celestial equator, without having...
  12. M

    Ian Morisson's Introduction to Astronomy and Cosmology questions

    Hey there! I recently bought said book and would highly recommend it for any Astronomy and Cosmology undergrads. However, one little niggling thing about it (something that grinds my gears in general with textbooks) is that it features end of chapter questions yet no set of answers for the...
  13. L

    Astronomy paper help - professor doesn't understand my wording

    Hiya, First off, I'm not sure where to post this topic. I was thinking either the homework section, or General Astronomy, but I chose to put it here because my question relates to a research paper in Astronomy. Let me discuss the basics of the paper. We have to pick a topic in the 1920s that...
  14. N

    Solve Spherical Astronomy Homework - Max Time & Side of World

    This homework is for someone who understands the spherical astronomy and physics. I do not understand subject matter. I can do the basics - I know some kinds of coordinates, but that's all. Please be very patient with me. Homework Statement Astronomer observing the sky with a small telescope...
  15. D

    For someone wanting to work in astronomy

    For someone wanting to work in astronomy... ...is an Astrophysics degree the way to go or should I go with Physics? I'm a first-year undergrad who sort of spent the past semester and a half thinking I'd be a History major. I have a strong interest in astronomy and would love to work in the...
  16. N

    Good Books for Astronomy Olympiad

    I am a high school student starting grade 11 . I am preparing for physics olympiad and i have a solid knowledge of theory upto the level of RESNICK HALLIDAY . I leant Calculus,Analytic Geometry,Trigonometry,Differential eqns and Higher algebra . So i am preparing to go for Astronomy Olympiad...
  17. N

    The future of Radio Astronomy (your thoughts)

    "The future of Radio Astronomy" (your thoughts) Hello all, I'm doing an extended project on "the future of radio astronomy". And I would like to know people's opinions on the "future of radio astronomy" and what advancements the field of radio astronomy is expected to make in the future...
  18. A

    Can you recommend any resources for Astronomy?

    Hey! I'm doing Science Olympiads and my category is Astronomy. We're allowed to bring in a laptop with whatever we want on it but it just can't connect to the internet. Can you recommend any software, databases, or etc that would be useful to have? Normally, the questions are basic...
  19. T

    Visual respresentations of topics in Astronomy

    Hello everyone. It is exciting to discover your forum here. I am hoping someone might be able to point me in the right direction for finding any symbols, charts, diagrams, written formulas, et cetera (ANYTHING) that represents or communicates or otherwise serves to explain any of the...
  20. N

    What is the purpose of heterodyning in radio astronomy?

    Hello all, I'm aware that heterodyning is a radio signal processing technique as kindly explained by the Wiki article on the topic (http://en.wikipedia.org/wiki/Heterodyne). However I don't understand how radio astronomers use this technique to aid their observations, what sort of...
  21. L

    What is the equation for calculating signal-to-noise ratio in astronomy?

    Homework Statement You observe a star with a count rate of 0.1 counts per second and the background is 0.05 counts per second. (a) How long do you need to observe for in order to detect 100 counts from the star? [2] - 1000 seconds (b) Estimate the signal-to-noise reached in the exposure...
  22. K

    Programs Can I PhD in astronomy with an electronics engg degree?

    Hi, I am currently studying electronics engineering in India and I plan to start applying for the fall 2013 semester within the next 2-3 weeks. I am pursuing a Masters' and PhD in astronomy and I will apply for the same. However, if I do not get an admit for this course from the universities I...
  23. A

    Physics vs physics with astronomy.

    Physics vs physcs with astronomy. I'm currently applying to College. I know I'm intersted in science. If it wasn't for this book about planets I had when I was 5 I'd prob nvr liked science. So my question is should I major in physics or a physics with an astronomy emphasis? What exactly is the...
  24. S

    Starting an Astronomy club - looking for tips?

    Hello! As my title suggests, I (twelve years old - not an adult) am starting an astronomy club at my school. I do want to take this rather seriously, and I am interested in accumulating several members. However, my main question in this forum is: What are some good topics to discuss in an...
  25. M

    Programs Undergraduate Degrees: Double Major In Astronomy and a Field of Biology

    Hello people, I am a grade 11 student in Ontario. I am currently facing a dilemma. Recently, I started thinking about my career, seeing as how I apply to university next year. I was considering options and I stopped to think; I want to do something I enjoy. I want a job that I don't see as...
  26. Greg Bernhardt

    Duke University Astronomy 101 Online Course

    Duke University is hosting a free course (video lectures) on "Introduction to Astronomy" by Ronen Plesser. Starts Nov 27th. Free to sign up! https://www.coursera.org/course/introastro
  27. bleist88

    Available Astronomy Research Topics?

    My astronomy lab group is planning a research project. We will have access to a .6 m reflecting telescope in the northern hemisphere as well as I believe a .6 or larger reflector in Australia remotely. We are curious how likely or practical it would be to be able to find research subjects...
  28. J

    Schools Schools for Astrophysics/ Astronomy

    Hello, I am a sophomore in high school and am looking to go into physics and ideally astrophysics. I am in honors precalc/trig right now and will be taking AP Calc next year, and probably multivariable calc my senior year. I'm in chemistry this year and physics next year. I will probably...
  29. L

    How Does Background Star Distance Affect Parallax Measurements?

    Homework Statement "Parallaxes are measured relative to background stars. If these are not infinitely distant themselves, then the parallax to the foreground object will be underestimated and its distance will be overestimated. Calculate the distance that will be measured to a star at a...
  30. P

    Physics Which Career Path in Science Should I Choose, Physics or Astronomy?

    i'm in year 9 or 9th grade (american) I'm 13 I'm going to be making my options for my exams in year 11th . I'm wanting to do something in the field of astronomy when I'm older but i also have a interest in physics as well but i know more about astronomy so does anyone recommend me what i should...
  31. T

    Is physics safer than astronomy (graduate level)?

    Hi guys, I want to first let everyone know that my upper level physics classes are going really well so far - I was definitely panicking for no reason and thank you to all who reassured me. I was wondering about grad school for astronomy vs physics. I have heard that it's better to do...
  32. D

    What is the easiest way to start college in Physics, Astrophysics, or Astronomy?

    I live in a home where we don't make very much money, but I would really like to go to school for Astrophysics. As of right now I do not know a lot as far as the mathematical processes go, so depending on where I were to get a scholarship or grant it might be rather difficult. What other ways...
  33. A

    Astronomy - synodic/sidereal periods

    Homework Statement Mars has a synodic period of 779.9 days and a sidereal period of 686.98 days. On 2/11/1990 Mars had an elongation of 43-deg W. The elongation of Mars 687 days later on 12/30/1901 was 15-deg W. What is the distance of Mars from Sun in AU units. (Hint: This is a multi-step...
  34. M

    Mathematical Physics vs. Honours Physics vs. Physics and Astronomy

    Hi, I'm a Grade 12 student and I'm very interested in physics. I would like to apply to Waterloo University becasue of their renowned Co-op program, but they have the three types on Physics Undergraduate Degrees; Mathematical Physics...
  35. A

    How Do You Convert Astronomical Units to Parsecs Using a Calculator?

    I actually need help with using my calculator for astronomy equations. I am trying to do conversions from astronomical units to parsecs and vice versa, and the answers I am getting do not make sense. I believe I am simply performing my order of operations incorrectly, but after hours of trying...
  36. F

    Astronomy with lab online class

    My name is Frederico Cantarelli. I am a Lindenwood University student, located in Saint Charles Missouri. I am senior level majoring in Business Admnistration! I will explain my situation on the lines below. For graduate in Business Admnistration at Lindenwood University, i will need 128...
  37. I

    How is the gain of a radio antenna at 230GHz calculated?

    Is it feasible to perform space VLBI at 230 GHz? Also how does one detect the radio jets at 230 GHz?
  38. U

    Physics1 honors vs astronomy regulars?

    A couple of my friends are going to switch out of physics honors for astronomy because they think its much easier and I want to know if it's easier. I did a little research and both use trigonometry so why would they go into astronomy ? Thoughts?
  39. M

    Programs A physics degree,specifically for astronomy?

    Hi my name is TJ, friends call me Muzzy, and I'm a programmer. I love programming. I love physics, but my knowledge of physics is well... very bad lol. I don't really plan to start a career somewhere as a physicist, but I want to learn it for my own research involving astronomy. I'm fascinated...
  40. wolfspirit

    The dereference between; astrophysics, astronomy, cosmology and space science

    hi i am looking at uni courses and i a a bit confused between the differences between; astrophysics, astronomy, cosmology and space science in terms of what is covered in each . Can anyone help please. Ryan
  41. A

    Can anyone recommend any astronomy books

    Just looking for some books that includes topics like evolution of stars, pulsar and quasar and the solar system.
  42. R

    Studying Studying Astronomy after Systems Engineering?

    Hi, I'm in my second year (out of 5) of Systems Engineering. I would love to study Astronomy (which is also a 5 year career) after I get my degree, but I don't know how useful it would be to finish studying that late, and I'm not sure how useful it would be to have both degrees. Obviously I'd...
  43. D

    Astronomy question - Sidereal time calculation

    Homework Statement (a) Calculate sidereal time at 11am on December 8th of any year. (b) Calculate the Greenwich Sidereal Time when the local sidereal time on longitude 20 degrees (West) is 20h 45m. Homework Equations I know from my notes that a Sidereal day is 4 minutes shorter than...
  44. M

    Science Fair Project Ideas for Astronomy

    Hey there guys! I haven't been on this forum a while, been busy with school work and assessments, but still catching up on astronomical developments and physical advancements (Higgs Boson around the corner soon?!) Anyways, as the title suggests, I'm definitely entering a local science fair...
  45. T

    Astronomy or planetary science?

    My main interest in physics is b/c of astronomy. I'm doing physics undergrad as a stepping stone to grad school astronomy/astrophysics. However upon introspection I notice that my main interest in space lies in the solar system and exoplanets and the potential for life. Is astronomy then the...
  46. F

    Focal Length problem for astronomy class

    Homework Statement A telescope has a focal ratio of f/7.5. You wish to use it with a spectrometer that requires an f/10 beam at its input. Compute the focal length of a 50mm diameter lens that, when inserted in the beam 150mm in front of the unmodified focal plane, produces the required beam...
  47. G

    Astronomy - Hohmann Transfer Orbit

    The most efficient way to reach Mars from Earth is following the Hohmann Transfer Orbit (Wolfgang Hohmann, 1925). A spaceship must first get free of Earth (it still orbits the Sun together with Earth, at 30 km/s, at a distance of 1 AU), then it adds speed so that its aphelion (in its orbit...
  48. N

    Physics or Astronomy informative speech ideas?

    I need some ideas for a physics or astronomy related speech?
  49. P

    Programs Should I Pursue an Astronomy Degree?

    Hi guys, I am wondering whether I would be taken seriously by the admissions committees if I were to apply for a B.S. degree in Physics-Astronomy (concentration) because I am in the social sciences, getting my M.A. in a social science field this May. I want to earn my Ph.D. in Astronomy...
  50. N

    Is anyone familiar with The Open Astronomy Journal?

    http://www.benthamscience.com/open/toaaj/index.htm, published as part of http://www.benthamscience.com/open/index.htm. From the website:
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