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This module covers basic astronomy with a modern observational approach. It encompasses two broad themes of ‘Stars and Galaxies’ and ‘Multiwavelength Astronomy’. Starting from cosmic length scales, learn how astronomers measure the Universe – through spectroscopy, imaging and time-variability. You’ll learn about the constituents of stars and galaxies, and study their formation, evolution and rebirth through energetic processes. To finish, revisit the Universe from the perspective of cosmic time scales. Throughout, alongside astronomy, you’ll develop your computing, maths and physics skills.

What you will study

First, you’ll look at some astronomy fundamentals. You’ll learn how modern astronomers measure the universe, considering spectroscopy, imaging and time-variability as observational tools.

Topic 1: Cosmic length scales
Starting with the sizes of things, this topic explains astrometry – how we measure positions of astronomical objects. Then photometry – how we measure the brightness of such objects. Eventually, we’ll combine both concepts to see how we can measure distances in the Universe.

Topic 2: The spectral Universe
You’ll begin by understanding how continuum emission or black body radiation enables astronomers to determine stellar temperatures, radii and luminosities. And learn about energetic processes in evolving galaxies. You’ll move on to understand absorption and emission spectroscopy, in particular, how astronomers use stellar spectroscopy to classify stars. Leading to the Hertzsprung–Russell diagram, a vital tool for understanding stars and stellar evolution. Finally, you’ll see how astronomers can exploit spectroscopy to look at how astronomical objects move through space relative to each other. And to look at motions within objects, focusing on the interior of stars, rotation of a spiral galaxy, or gas-turbulence in molecular clouds.

Topic 3: Mapping and classifying the Universe
You’ll exploit the multiwavelength view modern astronomy has of stars and galaxies. You’ll reach beyond pretty pictures to learn how we can quantitatively describe astronomical objects using measurements from images. See how we construct all-sky images from detailed telescopic surveys. And build a systematic understanding of the constituents of a galaxy, and where in a galaxy we find them. But we know we cannot see all the Universe, even with electromagnetic images – by the end of Topic 3, you’ll understand how we hunt for dark matter and black holes.
Having got the astronomy essentials under your belt, topics 4–6 focus on how we use mapping, imaging and spectroscopy tools to reveal the lifecycles of stars and galaxies.

Topic 4: Birth and life
This topic concentrates on how the action of a single force – gravity – can generate structure on all scales. From star formation, through stellar orbits, and onwards in scale, to galaxies and even the vast web-like structures that interconnect galaxies themselves. You’ll learn more about stars by studying the nearest star to us, the Sun. And understand the nuclear processes that fuel all stars at their core.

Topic 5: Evolution and death
This topic highlights what happens to nuclear processes in the final stages of stellar lifecycles. And the interplay between the lives of individual stars and the evolution of populations of stars within galaxies. You’ll see how the initial mass of a star plays a profound role in its eventual fate. Discover supernovae explosions, the formation of white dwarfs, neutron stars and red giants. Revise the Hertzsprung­–Russell diagram and trace the evolutionary track of stars. Delving into stellar archaeology, you’ll see how stellar populations reveal how galaxies change with time. And see how the abundance of chemical elements is linked to star-formation histories.

Topic 6: Extreme Universe
By ‘extreme Universe’, we mean environments that are extremely dense, extremely hot or have extremely high gravitational or magnetic fields. This leads to some of the most extreme events that happen in our Universe: from the impact of supermassive black holes that power active galaxies to binary star systems to pulsars. You’ll explore jets, outbursts and accretion processes. The topic finishes by describing the first detections of gravitational waves from merging pairs of black holes and neutron stars. And the emergence of multi-messenger astronomy – where gravitational and electromagnetic detections of astrophysical events are combined.

Topic 7: Cosmic timescales
Finally, in Topic 7 we synergise everything you’ve learned in S284 – looking from the perspective of cosmic timescales, rather than cosmic length scales. You’ll see how time-variability and time-domain astronomy is as important in understanding astrophysical processes as length scales and measurement techniques. You’ll identify how the Universe has evolved to its current state, and how it will evolve in the future. Having seen the importance of large-scale observational facilities to modern astronomy, and the need for multiwavelength and even multi-messenger telescopes, we close considering the impact of modern astronomy on the world at large. Whilst our quest for knowledge is unabated, what impact can the cost, building and situation of international observatories have on the local environment, customs or economy? What kinds of responsibilities must astronomers consider in their quest for ‘eyes on the Universe’?

You will learn

You’ll understand key ideas, concepts and principles in astronomy, across themes of time and distance, applied to stars and galaxies, including multiwavelength observational methods.

You’ll have gained skills that enable you to:

  • use appropriate searching, graphical, and mathematical methods to gather, analyse and interpret astronomical data and information
  • combine astronomical concepts with basic physics and mathematics, to solve unfamiliar problems
  • to understand limitations and ambiguity of astronomical measurements
  • produce coherent and clear written arguments in appropriate scientific language
  • use software and other tools to analyse and present data and models
  • acquire and analyse scientific information from a wide range of sources
  • carry out investigative science; make and accurately record observations; and use these to draw informed conclusions.

You’ll actively engage with the module community through contribution and participation, plan your learning, reflect on your development, and use these reflections to inform your future work.

Entry requirements

There are no formal entry requirements to study this module.

however, around a fifth of students studying OU level 2 astronomy each year are new to OU study; around half our astronomy students have never previously undertaken a physical sciences module. To study S284 successfully you must:

  • have at least ten hours study time a week
  • have studied S111, MST124 and SM123, or have a GCSE in Physics and Maths
  • be a competent computer user, including internet use and Office 365
  • have a strong command of reading and writing in English.

Without these, you might not be ready for S284.

Preparatory work

Are you ready for S284? is a diagnostic quiz to help you decide if you’re prepared to start studying S284.

What's included

S284 is mostly online. We’ll provide the study materials, study guide, activities, assignments, forums, online tutorial rooms and other resources, via a dedicated website. It contains many multimedia materials including audio tracks, videos and animations, as well as interactive activities, all of which help aid your understanding.

Where possible, the materials are also available in other formats – which may include PDF, EPUB, interactive ebook (EPUB3), Kindle ebook and Microsoft Word – to enable you to study on the move.

You’ll also receive a printed booklet for S284 – including extended summaries of the topics, plus the key equations.

Computing requirements

A computing device with a browser and broadband internet access is required for this module. Any modern browser will be suitable for most computer activities. Functionality may be limited on mobile devices.

Any additional software will be provided, or is generally freely available. However, some activities may have more specific requirements. For this reason, you will need to be able to install and run additional software on a device that meets the requirements below.

  • A desktop or laptop computer with an up-to-date version of Windows
  • The screen must have a resolution of at least 1024 pixels horizontally and 768 pixels vertically.

To join in the spoken conversation in our online rooms we recommend a headset (headphones or earphones with an integrated microphone).

Our Skills for OU study website has further information including computing skills for study, computer security, acquiring a computer and Microsoft software offers for students.

Teaching and assessment

Support from your tutor

Throughout your module studies, you’ll get help and support from your assigned module tutor. They’ll help you by:

  • Marking your assignments (TMAs) and providing detailed feedback for you to improve.
  • Guiding you to additional learning resources.
  • Providing individual guidance, whether that’s for general study skills or specific module content.
  • Facilitating online discussions between your fellow students, in the dedicated module and tutor group forums.

Module tutors also run online tutorials throughout the module. Where possible, recordings of online tutorials will be made available to students. While these tutorials won’t be compulsory for you to complete the module, you’re strongly encouraged to take part. If you want to participate, you’ll likely need a headset with a microphone.


The assessment details for this module can be found in the facts box.

This module has six Tutor-Marked Assignments (TMAs). You must submit them as Microsoft Word™ documents via the online electronic TMA submission system. Expect each TMA to take you up to three hours to complete. Each is worth 8% of your overall assessment score for the module. They are evenly spaced, approximately one a month, throughout the module. The TMAs are shorter than those you may have met on other modules, and you can often partially complete them by simply working through the preceding module materials.

Online exams1
There is also an online exam. You’ll take it in two parts, one in January (study week 14) and one in May (study week 31). Each part must be taken within the specified week, but at a time of your choice, in your own place of study, using your own computer to submit your answers. The first part is worth 12% and the second part is worth 40% of your overall assessment score. You can’t pass this module without attempting at least one part of the exam.

1Listed as iCMAs in the 'Course work includes' box.

If you have a disability

The OU strives to make all aspects of study accessible to everyone and this Accessibility Statement outlines what studying S284 involves. You should use this information to inform your study preparations and any discussions with us about how we can meet your needs.

Future availability

Astronomy (S284) starts once a year – in October.

This page describes the module that will start in October 2021.

We expect it to start for the last time in October 2027.

Course work includes:

6 Tutor-marked assignments (TMAs)
2 Interactive computer-marked assignments (iCMAs)
End-of-module assessment
No residential school