Ice at the Poles on the Moon

It’s Cold Out There (but Icy!)

People have long suspected that there’s ice at the poles of the Moon. Data taken when a probe crashed into the lunar south pole some years ago showed tantalizing evidence that it was there. Other studies have also hinted at the presence of ice at the poles. Now, scientists have observed direct evidence of icy deposits in shadowed regions in craters. It could be very ancient ice, perhaps left behind after comet impacts in the distant past.

So how do scientists who study the Moon know this?

NASA Jet Propulsion Laboratory researchers working on a spacecraft instrument team found very specific signatures of ice in data from their M3 instrument that is mounted on India’s Chandrayaan-1 spacecraft. M3 stands for “Moon Mineralogy Mapper”. It detected reflections from ice and the data showed that molecules in the material that was doing the reflecting are typical of water ice.

Ice can survive on the Moon at these polar regions because it is protected from direct sunlight by surface rocks in the crater rims where the ices lie. The temperatures are very cold there, never getting much higher than -250 F (-156.7 C).

Implications of Ice on the Moon

As nations and space agencies look toward future bases and habitations on the Moon, the big question is always, “How do we get enough water there to support the crews and inhabitants?” The lunar ices may provide one avenue for water sources, and other scientists are looking at water stored away inside porous rocks. Wherever it comes from, water is the major requirement for successful lunar exploration. So, studies like this one help uncover sources for the future explorers and tell us more about the Moon’s history.

You can read more about this finding at NASA’s JPL site.

Mystery in the Outer Solar System

One Giant Planet X or Actions of Little Worlds?

The outer solar system is a mysterious place. No, it isn’t filled with monsters and ghosts. Not that kind of mysterious. Instead, it’s a mystery because we haven’t explored even a tiny percentage of it. Sure, the New Horizons spacecraft is heading out through it and has explored Pluto. But, it’s one tiny spacecraft and space is very big. There ARE worlds out there, as we know from previous ground-based discoveries of Sedna, Eris, Quaoar, and so on. And, there have been hints of something big out there—really big. Is it a large world? Or could it be something else?

Gravity tells a Tale of Sedna’s Orbit

sedna
An artist’s conception of Sedna, a dwarf planet in the Kuiper Belt. Credit: NASA/JPL-Caltech

The main way we “know” something is out there is because there’s a gravitational perturbation affecting the known worlds in the Kuiper Belt. Whatever it is, it’s causing those orbits to change a tiny bit, and that’s measurable by telescopes here on Earth. Planetary scientist Mike Brown of CalTech suggested that it’s a big Planet X, some monster world with enough mass and gravity to tug on orbits of smaller worlds. That’s entirely possible. But, it hasn’t been observed yet. So, that’s a bit of a problem.

What if the perturbations weren’t from some giant world out there, but a combination of gravitational interactions of smaller bodies on each other? That’s the idea behind a theory that seeks to explain some planetary oddities that exist far from the Sun. Take Sedna, for example. It orbits out at a distance of 12 billion km (8 billion miles) from the Sun, and it’s part of the solar system, but appears separated in its orbit from the other worlds out there.

Astronomers at the University of Colorado suggest that, instead of some large body disturbing the orbit of dwarf planet Sedna and other worlds, there may be another explanation. They calculated that the orbits of Sedna and other worlds may be perturbed it and other worlds jostling against each other and space debris in the outer solar system. Interactions (although not necessarily collisions) could affect orbits.

Studying the Orbit of Sedna

The orbits of places such as Sedna, which are often referred to as “detached objects”, have large, circular orbits that don’t really get close to Jupiter or Neptune, and it’s not clear how they got to the outer solar system. Orbital dynamics of outer solar system objects (that is, the motions they experience as they orbit) comprise a lot of computer simulations going on right now. One outcome suggests that small-scale interactions of bodies in the solar system can act on their orbits (and even on larger bodies). And those kinds of interactions may well have affected Sedna’s orbit, circularizing it and making it “detached”. It also means that smaller objects “out there” may still be affecting the orbits of worlds such as Sedna, and giving the appearance of something “really big” doing the perturbing.

Of course, the theory needs to be backed up with observations of those distant places, or even one big world. So far, all planetary scientists have is the tantalizing clue that gravitational tugs are affecting orbits. It could be one big place or a lot of little ones.

Exploring Science and the Cosmos

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