The phrase "astonishing to learn" is correct and usable in written English.
It can be used when expressing surprise or disbelief about a piece of information that has been revealed or discovered.
Example: "It was astonishing to learn that the ancient civilization had advanced technology far beyond what we previously thought."
Alternatives: "surprising to discover" or "amazing to find out".
It is astonishing to learn that some stores have seven tiers of management between the shop floor and the store manager.
And it is pleasantly astonishing to learn that in the Florence of the 1300's each person drank a gallon of wine a week.
It is astonishing to learn that events of years gone by are encoded in the brain in a pattern of electrical and chemical connections, but the technical details can still be confusing.
The President's Cancer Panel is the Mount Everest of the medical mainstream, so it is astonishing to learn that it is poised to join ranks with the organic food movement and declare: chemicals threaten our bodies.
It's truly astonishing to learn that this beautiful, evocative district is threatened by over-zealous town planners.
This, as well as other amazing and strange aspects of our evolutionary history called attention to by Shubin, was astonishing to learn about.
(It is almost equally astonishing to learn--after watching this performance--that the 22-year-old Platt headed the Chicago company of The Book of Mormon as the buffoonish Elder Cunningham. He presumably grew up under the influence of Wicked, as his father is the top-billed producer of that blockbuster, but his performance certainly speaks for itself).
O'Neill and others like him were in a race with Al Qaeda, and although we know how the race ended, it's astonishing — and heartbreaking — to learn how close it was.
It's astonishing, given all this, to learn that the whole project cost just less than $1 million to build, 84% of it paid by the federal government.
I find it tragic and astonishing that some governments need to learn this lesson again.
