He forever changed the way women are diagnosed with cervical cancer.

If you've looked anything up today, you might have wondered why Google's logo features a sketch of a scientist. The featured man, Georgios Papanikolaou, is the inventor of the Pap test, which is used to diagnose cervical cancer and precancerous conditions that can be treated.

Papanikolaou, born on this day in 1883, first published research on the Pap test, also called a Pap smear, in 1928, though his work went pretty much unnoticed at the time. He then co-authored a 1943 book called Diagnosis of Uterine Cancer by the Vaginal Smear.

Some research suggests that thanks to the Pap test, the cervical cancer death rate in the U.S. has gone from up to 10 in every 1,000 women to 2 in every 1,000. The test is usually painless and incredibly simple, taking only a few minutes. It allows doctors to diagnose and treat cervical cancer early on in the disease's progression.

When you get a Pap test, your doctor first inserts a tool called a speculum into your vagina. The speculum separates the vaginal walls so that your doctor can examine your cervix, the narrow end of the uterus found at the top of the vagina. This may cause you to feel some pressure, but, again, pain is usually not felt during a Pap test.

Your doctor will then use a soft brush with what's called a spatula, which is a flat scarping tool. Your doctor will collect samples of cervical cells, which will then be sent to a lab and evaluated. Even if the cells do not come back with a cancer diagnosis, your doctor might observe an abnormality that could signal the future presence of cervical cancer cells.

The CDC recommends that average-risk women ages 21 to 65 get a Pap test every three years.

Papanikolaou, who was born in Greece and moved to America, died from a heart attack in 1962. But decades later, a 1998 article on the Pap test described his contribution to women's medical care this way: "This is the story of an ambitious and brilliant man, Georgios Papanikolaou, and his devoted wife, Andromache Mavroyenous, whose discovery of the screening test is now recognized as the most significant advance in the control of cancer in the 20th century."