Astronomers believe the most likely number of advanced alien civilisations living in the Milky Way is 36.
Scientists at the University of Nottingham worked on the assumption* that intelligent life on other planets is similar to humans.
They then calculated* there could be as many as 36 alien races out there that are capable* of sending radio signals.
However, they think the average distance to one of these civilisations would be 17,000 light-years*.
This would make communicating with them difficult with our current technology.
The calculation could help us better understand how long into the future humans could expect to live on Earth.
Lead researcher and Professor of Astrophysics at the University of Nottingham, UK, Christopher Conselice, explained they came up with the number 36 partly by considering how long it took humans to come into being on Earth after Earth formed. They then looked at the number of opportunities for complex alien life to form on other planets in a similar timescale.
“There should be at least a few dozen active civilisations in our Galaxy* under the assumption that it takes 5 billion years for intelligent life to form on other planets, as on Earth,” Prof Conselice said.
“The idea is looking at evolution, but on a cosmic* scale. We call this calculation the Astrobiological Copernican Limit.”
The two Astrobiological Copernican limits are that intelligent life forms in less than 5 billion years, or after about 5 billion years — similar to on Earth where a communicating civilisation formed after 4.5 billion years.
The researchers think the other civilisations may be sending out signals and that our chances of detecting them depends on how long these signals have been sent for.
We’ve had our signal technology for around 100 years so the astronomers hope an alien race developing at the same rate would have the same signal ability at the same time.
Prof Conselice said the research could give us clues to how long our own civilisation on Earth could last.
“If we find that intelligent life is common then this would reveal that our civilisation could exist for much longer than a few hundred years, alternatively if we find that there are no active civilisations in our Galaxy it is a bad sign for our own long-term existence.
“By searching for extraterrestrial* intelligent life — even if we find nothing — we are discovering our own future and fate.”
The study is published in The Astrophysical Journal.
This article was published on The Sun and is republished here with permission.
Many astronomers have tried to figure out ways to calculate whether and how many alien life forms exist in space. There is a lot of disagreement about how to do it and we are unlikely ever to know the correct answer.
One of the most famous attempts was in 1961 by astronomer Frank Drake. He said that to calculate an answer, we would need to know the value of seven factors. Unfortunately, we can only know the answer to the first factor.
Drake’s factors were:
- Average number of stars to form a year in the Milky Way galaxy.
- Fraction of those stars that form planets.
- Fraction of those planets that could support life.
- Fraction of life-supporting planets that form life.
- Fraction of those living planets that develop intelligent life forms.
- Fraction of those intelligent life forms that develop technology.
- Average lifetime of a communicating species (how long a civilisation will put radio signals into space for us to hear).
- assumption: estimate or calculated guess based on some known things
- calculated: worked out
- capable: able to do something
- light-years: distance light travels in one year
- galaxy: the Milky Way
- cosmic: from space beyond Earth and its atmosphere
- extraterrestrial: not on Earth
- How many alien civilisations do the astronomers estimate exist?
- What is our galaxy called?
- How long have we had signals technology on Earth?
- What could this kind of research tell us about life on Earth?
- Who is Frank Drake? What did he do?
LISTEN TO THIS STORY
1. Alien Existence
Imagine an alien civilisation on another planet is trying to send signals to us on Earth, wondering the same thing as us … is there anyone/anything else out there?
Write a narrative about an alien civilisation finally making contact with someone here on Earth and comparing notes about their planets.
Ensure your narrative has an orientation, complication and resolution. Make it fun and interesting by putting yourself in the shoes of your characters … how would you explain our planet and daily life to an alien, and vice versa!
Give your story a title, proofread and edit your draft and then publish for your classmates and family to read and enjoy. If you are proud of your work you might consider entering it into the Kids News Short Story competition on the website.
Time: allow 60 minutes to complete this activity
Curriculum Links: English, Critical and creative thinking
There could be as many as 36 alien races in the Galaxy according to this research. Work with a partner and name and (using your imagination) describe at least three of these races and how they differ from each other.
Time: allow 20 minutes to complete this activity
Curriculum Links: English, Critical and creative thinking
Grammar and VCOP
The glossary of terms helps you to understand and learn the ambitious vocabulary being used in the article. Can you use the words outlined in the glossary to create new sentences? Challenge yourself to include other VCOP (vocabulary, connectives, openers and punctuation) elements in your sentence/s. Have another look through the article, can you find any other Wow Words not outlined in the glossary?
HAVE YOUR SAY: Do you think there are 36 alien civilisations?
No one-word answers. Use full sentences to explain your thinking. No comments will be published until approved by editors.