Extra-terrestrial life is the existence of life outside of the Earth. Are we alone in the universe? So far the only life we know about inhabits our planet – Earth – but there are planets that orbit other stars in a similar way to how the Earth orbits the Sun.

Curriculum links

Data, evidence, theories and explanations 1a. how scientific data can be collected and analysed
1b. how interpretation of data, using creative thought, provides evidence to test ideas and develop theories
1d. that there are some questions that science cannot currently answer, and some that science cannot address.
Applications and implications of science 4c. how uncertainties in scientific knowledge and scientific ideas change over time and about the role of the scientific community in validating these changes.
Energy, electricity and radiations 7c. radiations, including ionising radiations, can transfer energy and radiations in the form of waves can be used for communication.
Environment, Earth and universe 8a. the effects of human activity on the environment can be assessed using living and non-living indicators
8b. the surface and the atmosphere of the Earth have changed since the Earth's origin and are changing at present
8c. the solar system is part of the universe, which has changed since its origin and continues to show long-term changes.

Scottish Curriculum

Science - Curriculum for Excellence level 4 SCN 3-06a. Planet Earth - Space: By using my knowledge of our solar system and the basic needs of living things, I can produce a reasoned argument on the likelihood of life existing elsewhere in the universe
SCN 4-06a. By researching developments used to observe or explore space, I can illustrate how our knowledge of the universe has evolved over time.
SCN 4-11b. Forces, electricity and waves - Vibrations and waves: By carrying out a comparison of the properties of parts of the electromagnetic spectrum beyond the visible, I can explain the use of radiation and discuss how this has impacted upon society and our quality of life
SCN 4-20a. Topical Science: I have researched new developments in science and can explain how their current or future applications might impact on modern life
SCN 4-20b. Having selected scientific themes of topical interest, I can critically analyse the issues, and use relevant information to develop an informed argument
Environmental Science National 4 & 5 Potentially relevant to modules: Earth's Resources (living and non-living environment components of the Earth).

Physics National 4 & 5

Potentially relevant to modules: Space (solar system and its exploration.


Why is the search for extra-terrestrial life important?

What is the search for extra-terrestrial life all about?

lagoon nebulaExtra-terrestrial life is the existence of life outside of the Earth.

All the atoms in our bodies and the environment around us came from nuclear fusion reactions in ancient stars and supernova explosions, where heavier elements are made by fusing smaller atoms together.  These elements came together on Earth under the right conditions to create life. Is it possible that the same atoms could exist on other planets with life forms on them somewhere else in universe? Are we alone in the universe? It is the subject of many books and films with both comical and disastrous storylines.

In the last 15 years, scientists have proved the existence of planets that orbit other stars in a similar way to how the Earth orbits the Sun. About 20 planets have been identified that are rocky and could possibly have conditions suitable for life, but so far the only life we know about inhabits our planet - Earth. In fact, compared with the overall size of Earth, life is only found in tiny region of it. If the Earth was like an apple, the area where life is found (called the biosphere) would be like the skin of the apple.  However, living organisms have been found as deep as 10 km within the Earth's crust, and about 10 km above the surface of the sea.

Why is this important?

Searching for life in other parts of the universe is also a way of answering questions about ourselves. Where did we come from? Why are we here? Where will we be going? The question of whether we are alone in the universe still remains unanswered, with no scientific evidence yet to confirm one possible outcome or the other.