Scots scientist Mary Somerville is being celebrated with a Google Doodle on its UK homepage.
The firm said it wanted to honour "one of the greatest intellectual writers of the 19th Century".
The illustration of the Jedburgh-born mathematician and astronomer will appear on the page for 24 hours.
Google said her books were some of the most popular scientific publications of her time "opening the door for generations of female scientists".
Somerville enjoyed similar recognition a few years ago when it was announced she would appear on the new Royal Bank of Scotland £10 note.
The company said it wanted to recognise her "immense contribution to science and her determination to succeed against all the odds".
Who was Mary Somerville?
By BBC Scotland science correspondent Kenneth Macdonald
Mary Fairfax Somerville was a mathematician, geographer and astronomer, who was born in 1780 in Jedburgh but her childhood home was at Burntisland in Fife.
Her parents tried to stop her studying because they thought it would kill her. Her sister had died and they thought studying was to blame.
But Mary ploughed on and carried out detailed and highly-accurate studies of the solar system.
She was so accurate that she noticed a wobble in the orbit of Uranus and suggested there could be another planet out there.
She was right. It was the planet Neptune.
Jointly with Caroline Herschel, she became the first female member of the Royal Astronomical Society.
Mary was also a huge advocate of women's rights, votes for women and women in education, which is why the formerly women-only Somerville College, Oxford, was named after her soon after her death in 1872.
Its alumni include former Indian prime minister Indira Ghandi and Margaret Thatcher, among others.
The Google Doodle is a temporary change made to the logo of its homepages to mark special events, achievements or people.
It has previously honoured the likes of American musician BB King, Austrian Nobel Prize winner Bertha von Suttner and French sculptor Camille Claudel.