#1: DNA Edited in Human Embryos

An international team of scientists has successfully used a new gene-editing technique to alter the DNA of several human embryos, correcting a defect that causes heart failure in young people. The accomplishment, the first using viable human embryos, could lead to the ability to eliminate genetic diseases in utero. Critics, however, oppose the creation of “genetically modified children,” leading to ethical debates and an uncertain future for the research.

#2: Invention Pulls Water Out of Thin Air

Above: This proof-of-concept device, built at MIT, demonstrates a new system for extracting drinking water from the air. The sequence of images at right shows how droplets of water accumulate over time as the inside temperature increases while exposed to the sun.

Using a special material called MOF and the power of the sun, scientists at MIT and the University of California, Berkeley, have developed a way to pull water out of dry air. The invention could pave the way for a solution to water scarcity, a critical problem for nearly half the people on Earth. The key component of the device is a metal-organic framework (MOF), a lattice of organic molecules and metal atoms. A kilogram of the customized MOF used in the device can pull several liters of water out of low-humidity air in desert regions.

#3: ‘Super-Earth’ Discovered

In April, scientists at Harvard’s MEarth Project announced a major finding: the discovery of an exoplanet that gives us the best opportunity yet to find alien life. Planet LHS 1140b is rocky, temperate, and just 40 light-years away (practically next door in astronomical terms), where it transits a star smaller than Earth. Among other factors, astronomers believe the planet could have liquid water on its surface, a necessity for life (as we know it) to exist. More: Derrick Pitts, Chief Astronomer at The Franklin Institute, breaks down the Top 10 Astronomy & Space Science Discoveries of 2017.

#4: Artificial Womb Keeps Fetal Lambs Alive

Scientists at the Children’s Hospital of Philadelphia successfully built an artificial womb that kept fetal lambs alive and developing normally, a breakthrough that could someday lead to saving premature babies born as early as 23 weeks. A clear plastic bag (dubbed a Biobag) filled with synthetic amniotic fluid serves as the “womb.” A machine outside the bag attaches to the lamb’s umbilical cord, serving as a placenta by providing nutrition and oxygen and removing waste. The research team hopes to test the artificial womb on premature human babies within five years.

#5: Neutron Star Collision Detected

In October 2017, astronomers detected something never seen before: light and gravitational waves from the same event. That event was the collision—observed two months earlier, also for the first time—of two neutron stars 130 million light-years from Earth in the constellation Hydra. The crash produced a massive explosion of energy and revealed these collisions as the source of heavy elements like gold, plutonium, and uranium. Most meaningful perhaps is the way the event was detected in the first place: by the observation of gravitational waves, ripples in the fabric of space-time first predicted by Albert Einstein in 1916 and observed directly just two years ago. The discovery propels us into the era of gravitational wave astronomy—and closer to uncovering the secrets of the universe.

#6: Secret Void Detected in Great Pyramid at Giza

Thanks to high-energy particle physics, scientists have found a previously unknown area in the Great Pyramid at Giza for the first time since the 1800s. Using muon radiography, which detects the subatomic particles called muons that are constantly raining down on Earth, the ScanPyramids project team detected a 100-foot-long cavity that could be a chamber, a ramp used to move blocks, or any number of other spaces. Muon particles pass through empty spaces more easily than they do solid areas, so muon detectors allow researchers to map solid and empty spaces inside a structure.

#7: Spinach Leaf Transformed Into Human Heart Tissue

Over lunch one day, scientists at Massachusetts’ Worcester Polytechnic Institute brainstormed ideas for solving the critical problem of not enough donor organs available. That lunch led to the successfultransformation of a spinach leaf into beating human heart tissue, a significant proof of concept that could lead to major breakthroughs, such as grafting damaged heart tissue. To create the spinach-heart hybrid, the team stripped green spinach leaves with detergent, which left behind a cellulose matrix loosely similar to the vascular structure of the heart. Then they seeded the vacated areas with cardiac muscle cells—and waited. Five days later, the cells began to beat.