A new study, conducted by the Australian Academy of Science, has found that just 59% of Australians know that the Earth's orbit of the sun takes a year, or a fraction more than 365 days.
Three in 10 people aren't aware that evolution is still occurring, with a similar proportion of the public dismissing the idea that humans influence evolution in other creatures.
On all of these measures, Australians' knowledge has declined in the past three years, when the academy last polled the public. The survey, undertaken by Auspoll, questioned 1,115 people.
The retrograde step in scientific knowledge is most pronounced in young people, with 12% fewer 18 to 24-year-olds knowing that Earth's orbit time compared to three years ago.