The word 'ascertain' is correct and usable in written English. You can use 'ascertain' to mean to find out or discover something as a result of investigation or analysis. For example: The team worked hard to ascertain the cause of the explosion.
Here's our round up of helpful articles and resources: Rosetta comet landing: everything you need to know This is a really handy compilation of six key things you need to know about the Rosetta mission, including how the findings will ascertain whether planets made the Earth blue and the size of 67P in relation to Manhattan, New York.
"We were able to use our experience as psychiatric nurses to ascertain whether or not Victor was genuine and whether or not what he was telling us was the truth.
Although the state of the economy remains difficult to ascertain beyond dubious official figures, huge sums are lost to corruption.
The EU urged the government to "take all necessary measures to ascertain Mr Dzamara's whereabouts", calling for a probe into the disappearance.
But the relief was suspended until further calculations could ascertain exactly how well the levels matched.
The feminist credentials of Suffragette are not difficult to ascertain – Mulligan doesn't play one of the Pankhursts, but rather a lowly footsoldier called Maud – but it is in Madding Crowd that Mulligan shows her cards.
Toxicology studies are also under way to ascertain whether the murderer gave the women any drugs or chemicals to render them unconscious.
When I feel like I can't trust my brain 100%, Ludwig really comes in handy. It makes me translate and proofread faster and my output more reliable.
Claudia Letizia
Head Translator and Proofreader @ organictranslations.eu