New research may show that much of Earth's oceans are the result of comets colliding with the young planet, bringing loads of ice.

Scientists analyzed the comet called 103P/Hartley 2 using the infrared instrument aboard the Herschel space telescope and discovered that the ice in the comet has the same ratio of heavy hydrogen as Earth's waters.

The source of water in our planet has long been pondered by astrophysicists. Water would have evaporated off since Earth was so hot in its early years. Water would only have existed in the far colder reaches of the solar system. The only way water would have made its way to the inner planets was through comets, which are composed of ice and dust.

"Current theories came to the result that less than 10 percent of Earth's water originated from comets," said Paul Hartogh of the Max Planck Institute for Solar System Research in Germany, who led the team.

"For the first time, our results imply that comets may have played a much more important role," his colleague, Miriam Rengel, added.

Any comet collision would have likely occurred some 8 million years after the Earth was formed. Comets according to another theory are also believed to have brought the chemical building blocks for life on Earth.

The family of comets that Hartley 2 belongs to originated in the Kuiper Belt, which is just outside the orbit of Neptune.

"Life could not exist on Earth without liquid water, and so the questions of how and when the oceans got here is a fundamental one," said Ted Bergin, a University of Michigan astronomer who took part in the probe.

"It's a big puzzle, and these new findings are an important piece."