Scan of 10.3 million stars doesn’t find aliens – yet

Scientists have looked for aliens in a scan of more than 10 million stars using a radio telescope in Western Australia.

It’s the broadest search for extraterrestrial life ever completed. So far, they haven’t found anything, though that doesn’t mean there isn’t life out there somewhere.

Seeking evidence of possible life beyond our solar system, the researchers are hunting for “technosignatures*” such as communications signals that may come from intelligent alien beings.

Using the Murchison Widefield Array (MWA) telescope in WA, they searched for low-frequency radio emissions — similar to FM radio frequencies — from about 10.3 million stars in the constellation of Vela. The findings were published this week in Publications of the Astronomical Society of Australia.

A “radio colour” view of the sky (showing radio signals coming in) above one section of the Murchison Widefield Array radio telescope, located in outback Western Australia. The Milky Way is visible as a band across the sky and the dots beyond are some of the galaxies observed by the telescope.

“It is not surprising that we didn’t find something. There are still so many unknown variables,” astrophysicist* Dr Chenoa Tremblay of the Astronomy and Space Science division of Australia’s national science agency, the Commonwealth Scientific and Industrial Research Organisation (CSIRO), said on Wednesday.

“The search for life outside of our solar system is a big challenge,” Dr Tremblay added. “We don’t know when, how, where or what type of signal we may receive to get an indication that we are not alone in the galaxy.”

While the search was 100 times deeper and broader than ever before, according to astrophysicist Professor Steven Tingay of Curtin University in Western Australia and the International Centre for Radio Astronomy Research, it involved relatively few stars in cosmic terms.

“Ten million stars does seem like a lot. However, our best evaluation is that there are around 100 billion stars (in the Milky Way galaxy). So we have only looked at about 0.001 per cent of our galaxy,” Dr Tremblay said.

“Pretend the oceans contained only 30 fish and we tried to look for them by testing an area the size of a backyard swimming pool. The chances of finding one of those fish would have been small.”

A close-up view of some of the The Murchison Widefield Array telescope in Murchison, WA. Picture: David Herne/ICRAR

The MWA is a forerunner* to another instrument, the Square Kilometre Array (SKA), that in the near future promises to boost the search for technosignatures.

“What is important is constantly improving the techniques and always going deeper and further,” Prof Tingay said. “There is always that chance that the next observation will be the one that turns up something, even if you expect nothing. Science can be surprising, so the important thing is to keep looking.”

Professor Steven Tingay at the International Centre for Radio Astronomy Research, Curtin University in Perth, WA, in 2011 with what was then new radio technology for the Murchison Wide-field Array.

GLOSSARY

• technosignatures: any measurable things or effects that provides scientific evidence of past or present technology
• astrophysicist: scientist who studies space and its physics
• forerunner: came before the next thing

EXTRA READING

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QUICK QUIZ

1. Where is the telescope?
2. Explain the analogy of the fish and the swimming pool.
3. How many stars are in the Milky Way?
4. What does MWA stand for? What is it?
5. What does Professor Tingay say is the important thing to keep doing?

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CLASSROOM ACTIVITIES
1. What Would Aliens Think?
Do you think that intelligent aliens would want us to find them? Imagine that you are an alien. Your planet has been able to watch earth for a long time, so you know about this research. Write a post or letter to Kids News giving your reaction to the news that humans are trying to look for aliens. Hint to get you started: what would be the benefits and possible problems for aliens?

Time: allow 20 minutes to complete this activity
Curriculum Links: English

2. Extension
‘Searching for alien life in space is a waste of time and money!’ Do you agree or disagree with this statement? Write a detailed explanation of your opinion. Your purpose is to persuade your reader that your opinion is correct.

Time: allow at least 20 minutes to complete this activity
Curriculum Links: English, Science

VCOP ACTIVITY
Verb adventures
With a partner see if you can identify all the doing words/verbs in this text. Highlight them in yellow and then make a list of them all down your page. Now see if you and your partner can come up with a synonym for the chosen verb. Make sure it still makes sense in the context it was taken from.

Try to replace some of the original verbs with your synonyms and discuss if any are better and why.

HAVE YOUR SAY: Do you think the scientists will ever find alien life? When? Where?
No one-word answers. Use full sentences to explain your thinking. No comments will be published until approved by editors.