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Exploring the Universe

3. What Light Can Tell Us: Spectra and Redshift

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In this mini-lecture, we explore how to use light to help us determine what materials are out there in the Universe. In particular, we consider: (i) Newton’s prism experiment, where white light is passed through a prism and the colours that make up the white light are bent by different amounts; (ii) continuous spectra vs. emission spectra; (iii) the emission spectra of various gases; (iv) familiar examples of emission spectra, such as sodium vapour streetlights and neon signs; (v) how emissions spectra can be used to determine gases in space; (vi) the Doppler effect and how it shows up in astronomy; (vii) an example of redshift, which allows us to measure the speed and direction of an faraway object; and (viii) the Hubble Ultra Deep Field.


In this course, Dr Pete Edwards (Durham University) provides an epic exploration of the Universe. In the first mini-lecture, we compare gravity on Earth to gravity in space, such as on the Moon and in orbits around planets. In the second mini-lecture, we take a look at the telescopes that have helped us see what’s out there in the Universe, before delving into the big picture of where our galaxy sits within the Universe. The third mini-lecture turns towards how we can use light — specifically something called an emission spectrum and a process called redshift — to understand what gases and materials are in the Universe. In the fourth mini-lecture, we discuss two important models of the Universe, the Big Bang Model and the Steady-State Model, that were both put forth to explain the discoveries made by Edwin Hubble in the first half of the 20th century. In the fifth mini-lecture, we look at star formation and the life cycle of stars, which is highly dependent on the star’s mass, specifically going into detail on red giants, supernova, white and black dwarfs, neutron stars, pulsars, and black holes.


Dr Pete Edwards is the Director of Science Outreach and the Science and Society Officer at Durham University. He is also a member of Durham University’s Astronomy and Astrophysics group. As the Director of Science Outreach at Durham University, Dr Edwards has developed a range of teaching resources aimed at primary and secondary students and teachers. He has visited one in three secondary schools in the UK, where he has provided a programme of physics demonstrations and talks. As an elected fellow of the Institute of Physics (IOP), he has contributed to the Teaching Astronomy and Space DVD (2010-2019) produced by the IOP, as well as the IOP videos How Big is the Universe? (2012) and The Expanding Universe and the Big Bang (2012). In 2005, he was chosen to deliver the 2006 IoP Schools’ and Colleges’ Lecture. This talk, Gravity, Gas and Stardust, was broadcast across the UK to over 12,000 14-16 year old students. He has also worked with TED to create the TED-Ed video, What light can teach us about the universe (2014). Dr Edwards is also a qualified secondary school teacher, who taught science and mathematics in various schools and colleges during the 1980’s before obtaining his Ph.D. and joining Durham University in 1990.

Cite this Lecture

APA style

Edwards, P. (2022, January 14). Exploring the Universe - What Light Can Tell Us: Spectra and Redshift [Video]. MASSOLIT.

MLA style

Edwards, P. "Exploring the Universe – What Light Can Tell Us: Spectra and Redshift." MASSOLIT, uploaded by MASSOLIT, 14 Jan 2022,

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