7 Earth-like planets, designer babies and a tower of human skulls: Best science discoveries of 2017

Here’s a quick recap of some of the most interesting scientific discoveries in 2017 that you may have missed.

WATCH: NASA discovers seven Earth-sized planets just 40 light years away

1:48 NASA discovers seven Earth-sized planets just 40 light years away

Earlier this year, NASA announced that they discovered seven Earth-sized planets 40 light years away that could possibly contain life.

The planets orbit a dim dwarf star, which is about the size of Jupiter, and three of the planets reside in what’s known as the “Goldilocks zone,” an area not too cold and not too hot where liquid water can form.

WATCH: Scientists used an artificial womb to grow lambs for four weeks

1:12 This lamb grew in an artificial womb

U.S. researchers have invented an external artificial womb that could help premature babies survive and develop fully.

So far, they grew lambs in a plastic bag which simulated a womb using amniotic fluids and an artificial umbilical cord.

Within four weeks, the baby lambs’ brains, lungs and other organs developed normally — they became conscious and grew wool.

WATCH: Saturn probe sends final transmission to NASA

0:56 Farewell, Cassini: Saturn probe sends final transmission to NASA

NASA’s Cassini probe went out with a bang this year after it was programmed to crash into Saturn as one last science experiment.

It collided with the gas giant at 113,000 km/hour, ending the 13-year mission which revealed Saturn’s beauty up close and provided NASA with new insights on its unique rings.

WATCH: Doctor explains the implications of U.S. scientists successfully repairing faulty DNA with gene editing

2:24 Dr. David Agus explains the implications of gene ‘fixing’

Gene editing came back in the spotlight in 2017 after U.S. researchers successfully used “CRISPR” to repair DNA mutations that cause early onset of heart disease.

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Currently, researchers are experimenting with human embryos to eliminate inherited diseases like Alzheimer’s and cystic fibrosis.

However, with the potential to eliminate a swath of chronic illnesses, the potential for a revival of eugenics could have problematic consequences if people start to design their babies’ genes for cosmetic purposes.

WATCH: Archaeologists discover tower of human skull buried in Mexico City

0:55 Tower of human skulls in Mexico casts new light on Aztecs

This may be one of the freakiest discoveries of the year when archaeologists found a tower consisting of hundreds of human skulls.

They believe that it may be part of the “Huey Tzompantli,” a legend told by Spanish conquistadores of a structure built out of human skulls.

WATCH: Scientists make 1st detection of light from gravitational wave source

2:05 Gold created by collision of stars

Back in 2016, scientists announced they found direct evidence of gravitational waves for the first time – something Albert Einstein predicted in his general theory of relativity.

In 2017, scientists detected gravitational waves from a source 130 million light years away, and within moments, detected a gamma ray burst from the same source.

The cosmic event was caused by two neutron stars, very dense remnants of dead stars, colliding.

WATCH: Researchers found secret chamber in Egypt’s Great Pyramid using cosmic-ray imaging

0:53 Researchers find mysterious hidden cavity inside Great Pyramid

Not since the 19th century has a new hidden chamber been found in the Great Pyramid of Giza.

Using cosmic-ray imaging, scientists were able to peer through the pyramid’s thick stones to find the 30-metre cavity.