Initial Publication Date: February 8, 2021

Origins of the Universe pcMEL

The Origins of the Universe pcMEL asks students to explore the connections between evidence and competing models about how the Universe began. It is one of the most fundamental and existential questions humans have asked.

Below are links to resources that will help students use the Origins of the Universe pcMEL to learn more about light spectra and characteristics of a universe changing through time.


This article provides an introduction to the Origins of the Universe MEL build-a-MEL (baMEL). It is useful even if you are using the Origins of the Universe pcMEL with your students. The primary difference between the pcMEL and the baMEL is that with the pcMEL students are given two models and four lines of evidence in a preconstructed diagram where as with the baMEL students choose two models from three and select four lines of evidence from eight to create their own MEL diagram.

The Origins build-a-MEL Article Cover
The Origins build-a-MEL (Acrobat (PDF) 492kB Feb8 21)

Next Generation Science Standards Performance Expectations

HS-ESS1-2: Earth's Place in the Universe

  • Construct an explanation of the Big Bang theory based on astronomical evidence of light spectra, motion of distant galaxies, and composition of matter in the universe.

The Models

Model A: Space, time, and matter came into existence a finite time ago in a hot dense state. It has been expanding and cooling ever since.
Model B: The Universe began a finite time ago when a small ball of matter exploded. The matter then spread out throughout space.

Student Handouts

Lines of Evidence

Evidence #1: Astronomers observe a uniform glow in the background of the sky no matter where we look.
Evidence #2: All galaxies are moving with space. Galaxies that are farther from Earth are moving faster than galaxies closer to Earth. Most galaxies are moving away from each other.
Evidence #3: The Universe has a predictable age based on its rate of expansion. Nothing in the Universe is older than that age.
Evidence #4: The Universe was once extremely hot and allowed for matter and energy to spontaneously convert back and forth into each other. Today, the Universe is far cooler than it once was.

Student Handouts

Other Resources

This Plausibility Ranking Task (PRT), which may be completed prior to using any MELs, helps students to understand the role of evidence in supporting or refuting models.

Virtual MEL

The Google Drive folder below contains MEL resource documents in the Google formats. In order to maximize the flexibility of our activities, the MEL Project Team wanted to make more resources compatible with virtual settings. We have made our MEL scaffolds available in Google formats, so that they can be copied, modified, and uploaded more easily on a variety of platforms and devices. Please note that to access all the materials for each MEL scaffold, you will need a Google account. View the README file first.

Digital Resources

Origin of Universe website
NASA's Origin of the Universe Group provides links to the missions and projects conducting research in this area and pointing to data, images and videos. The group is researching these questions: 1) What is the origin of the Universe? 2) What is the nature of Dark Energy? and 3) What will gravitational waves reveal?