Water Archives

December 6, 2021December 6, 2021 by Evan Gough

Did the Earth’s Water Come From the Sun?

The sun, solar winds and asteroid Itokawa. Image Credit: Curtin University.

Where did Earth’s water come from? Comets may have brought some of it. Asteroids may have brought some. Icy planetesimals may have played a role by crashing into the young Earth and depositing their water. Hydrogen from inside the Earth may have contributed, too. Another hypothesis states the collision that formed the Moon gave Earth its water.

There’s evidence to back up all of these hypotheses.

But new research suggests that the Sun and its Solar Wind may have helped delivered some water, too.

September 24, 2021September 24, 2021 by Evan Gough

Mars Was Too Small to Ever be Habitable

An artist's rendition of a Mars with Earth-like surface water. Image source: NASA Earth Observatory/Joshua Stevens; NOAA National Environmental Satellite, Data, and Information Service; NASA/JPL-Caltech/USGS; Graphic design by Sean Garcia/Washington University)

Mars and water. Those words can trigger an avalanche of speculation, evidence, hypotheses, and theories. Mars has some water now, but it’s frozen, and most of it’s buried. There’s only a tiny bit of water vapour in the atmosphere. Evidence shows that it was much wetter in the past. In its ancient past, the planet may have had a global ocean. But was it habitable at one time?

A new study says it wasn’t. Mars lost most of its water, and it’s all to do with the planet’s size.

July 4, 2021July 4, 2021 by Matt Williams

Unfortunately, There are Other Viable Explanations for the Subsurface Lakes on Mars

Mars’ south polar ice cap. Credit: ESA / DLR / FU Berlin /

Ever since 1971, when the Mariner 9 probe surveyed the surface of Mars, scientists have theorized that there might be subsurface ice beneath the southern polar ice cap on Mars. In 2004, the ESA’s Mars Express orbiter further confirmed this theory when its Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) instrument detected what looked like water ice at a depth of 3.7 km (2.3 mi) beneath the surface.

These findings were very encouraging since they indicated that there could still be sources of liquid water on Mars where life could survive. Unfortunately, after reviewing the MARSIS data, a team of researchers led from Arizona State University (ASU) has proposed an alternative explanation. As they indicated in a recent study, the radar reflections could be the result of clays, metal-bearing minerals, or saline ice beneath the surface.

February 3, 2021February 3, 2021 by Evan Gough

The Earth’s Magnetosphere Might be Creating Water on the Moon

Artist’s depiction of the Moon in the magnetosphere, with “Earth wind” made up of flowing oxygen ions (gray) and hydrogen ions (bright blue), which can react with the lunar surface to create water. The Moon spends >75% of its orbit in the solar wind (yellow), which is blocked by the magnetosphere the rest of the time. Credit: E. Masongsong, UCLA EPSS, NASA GSFC SVS.

There’s no doubt that the Moon has water on its surface. Orbiters have spotted deposits of ice persisting in the perpetual shadows of polar craters. And recent research shows that water exists in sunlit parts of the Moon, too.

Over the years, scientists have presented evidence that the Moon’s water came from comets, from asteroids, from inside the Moon, and even from the Sun.

But now new research is pointing the finger directly at Earth as the source of some of the Moon’s water.

November 23, 2020November 23, 2020 by Evan Gough

Mars Might Have Lost its Water Quickly

This artist's concept depicts the early Martian environment (right) – believed to contain liquid water and a thicker atmosphere – versus the cold, dry environment seen at Mars today (left). Image Credit: NASA's Goddard Space Flight Center

Mars is an arid place, and aside from a tiny amount of water vapour in the atmosphere, all water exists as ice. But it wasn’t always this arid. Evidence of the planet’s past wet chapter dots the surface. Paleolakes like Jezero Crater, soon to be explored by NASA’s Perseverance Rover, provide stark evidence of Mars’ ancient past. But what happened to all that water?

It disappeared into space, of course. But when? And how quickly?

November 19, 2020November 19, 2020 by Evan Gough

There Might Be Water On All Rocky Planets

Artist’s impression of a massive asteroid belt in orbit around a star. Earth's water may not have all come from asteroids and comets, so maybe that's true for exoplanets. Credit: NASA-JPL / Caltech / T. Pyle (SSC)

If you asked someone who was reasonably scientifically literate how Earth got its water, they’d likely tell you it came from asteroids—or maybe comets and planetesimals, too—that crashed into our planet in its early days. There’s detail, nuance, and uncertainty around that idea, but it’s widely believed to be the most likely reason that Earth has so much water.

But a new explanation for Earth’s water is emerging. It says that the water comes along for the ride when Earth formed out of the solar nebula.

If that’s correct, it means that most rocky planets might have water for at least a portion of their lives.