It’s time to redefine what qualifies as a planet

PLANET OR NOT? A group of planetary scientists label Pluto and many other orbs in the solar system as planets, despite the definition set down by the International Astronomical Union in 2006.

Pluto is a planet. It always has been, and it always will be, says Will Grundy of Lowell Observatory in Flagstaff, Arizona. Now he just has to convince the world of that.

For centuries, the word planet meant “wanderer” and included the sun, the moon, Mercury, Venus, Mars, Jupiter and Saturn. Eventually the moon and sun were dropped from the definition, but Pluto was included, after its discovery in 1930. That idea of a planet as a rocky or gaseous body that orbited the sun stuck, all the way up until 2006.

Then, the International Astronomical Union narrowed the definition, describing a planet as any round object that orbits the sun and has moved any pesky neighbors out of its way, either by consuming them or flinging them off into space. Pluto failed to meet the last criterion (SN: 9/2/06, p. 149), so it was demoted to a dwarf planet.

Almost overnight, the solar system was down to eight planets. “The public took notice,” Grundy says. It latched onto the IAU’s definition — perhaps a bit prematurely. The definition has flaws, he and other planetary scientists argue. First, it discounts the thousands of…

The Planetary Society Has a Few Tips for the President

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As the CEO of The Planetary Society, Bill Nye has written an open letter to President Trump, highlighting the need for prioritizing space research, and for supporting NASA’s space exploration efforts in particular. Bill Nye offers the president a comprehensive five-point plan for steering NASA’s objectives and orientation during his tenure:

1. Keep Mars as the Goal
Mars became the central objective of NASA’s efforts during the previous administration, and Bill Nye urges a continued focus on the same path. It is also important to insist on Mars because there are voices in the Trump administration that want to divert resources away from the Red Planet and focus on exploration of the moon. A vocal example of this is Newt Gingrich who has advocated “a permanent moon base”. For Bill Nye and The Planetary Society, a diversion of efforts to the moon would mean that a manned mission to Mars might be delayed by a generation.

2. Orbit Mars First
This point has emerged from earlier work at The Planetary Society, such as workshops on solving problems of inhabiting Mars, which have found that orbital engagement should precede a full landing on the Red Planet. This was the original strategy for the moon landing, where Apollo VIII orbited the moon and Apollo XI landed on it. The Planetary Society has suggested that in an orbital-first strategy, humans can be stationed in Mars’ orbit by 2033, and thereafter landed on the Mars surface by 2039.

3. Expand NASA’s Scientific Programs
Bill Nye draws attention to the ‘jobs’ element of NASA’s contribution, pointing out that there are tens of thousands of high-skilled jobs in engineering, manufacturing, and the pure sciences, that exist specifically thanks to NASA’s scientific programs. The report recommends that “at least 30 percent of NASA’s total budget be committed to its Science Mission Directorate,” and that we don’t forget two things: our curiosity and safety. A budget commitment to the science mission “will help humanity better understand its origins, protect us from solar storms, search for life beyond Earth, as well as understand our changing climate,” says the report. NASA’s acting administrator, Robert Lightfoot, has already stated that because of Trump’s proposed budget, the agency “will not pursue the Asteroid Redirect Mission (ARM).” Here’s why that matters. Trump signed the ‘NASA Transition Authorization Act of 2017’ on March 21, which seems to favor stability over progress, leaving…

In new Cassini portraits, Saturn’s moon Pan looks like pasta

Pan in Cassini image
This week, Cassini captured the closest images ever taken of Pan, a small moon that orbits amid Saturn’s rings.

Saturn serves up the closest thing to space pasta, the latest round of images from NASA’s Cassini probe, released March 9, show.

On March 7, the spacecraft snapped a series of portraits of Pan, Saturn’s small moon that orbits within a 325-kilometer gap in one of the planet’s rings. Taken at a distance of 24,572 kilometers from the moon, these are the closest images of Pan to date.

The close-ups could help refine astronomers’ understanding of the mini moon’s geology and…

Look Up! It’s the Snow Moon Lunar Eclipse Comet Spectacular

Last year it was all supermoons, all the time. This year it’s going to be eclipses. There’s the big one on August 21—start planning your trip now!—and leading up to it are a couple of smaller events, starting with a penumbral lunar eclipse tonight, and an annular solar eclipse later this month. The eclipse tomorrow night, February 10, will occur during a “Snow Moon,” and if you stay up a little bit longer, you might even be able to spot a comet. In other words, if you’re looking for cheap date ideas for the last Friday before Valentine’s Day, you’ve come to the right place.

Full moons have names. They survive largely through the pages of the Farmer’s Almanac, a 99-year-old annual best known for its weather predictions. You might recall the Hunter’s Moon, or the Harvest Moon, and who could forget the Beaver Moon?

Tonight’s moon is called the Snow Moon, named by the American Indians for the obvious reason: February is the snowiest month. (This moon was also sometimes called the “Hunger Moon,” for the same reason, and the “Shoulder to Shoulder Around the Fire Moon.”) Generally speaking, you get only one full moon per month. In fact, the word “month” is derived from “moon,” referring to a full cycle of its phases. Next month is the Worm Moon, because with the onset of spring, you have the wormiest month. And so on.

If you decide to have a moonlit picnic with your sweetheart, that kind of trivia is solid gold.

So what of this eclipse business? You might notice also that the moon seems a little … off. I don’t…

The Apollo Astronaut Who Was Allergic to the Moon

The inside of Apollo 17’s lunar module smelled of gunpowder. It was December 1972, the last of NASA’s manned moon missions, and astronauts Eugene Cernan and Harrison “Jack” Schmitt had just finished a successful survey of the Valley of Taurus-Littrow, a spot on the southeastern “coast” of the Moon’s Sea of Serenity. They had returned to the landing module with their spacesuits caked in moondust.

The men brushed themselves off and removed their helmets. Suddenly, Schmitt began having a sneezing fit. His eyes reddened. His throat itched. His sinuses clogged.

“I didn’t know I had lunar dust hay fever,” Schmitt said. Listening in, men stationed back on Earth began to bust Schmitt’s chops over the radio transmission. “It’s funny they don’t check for that,” said Joseph Allen at Mission Control. “Maybe that’s the trouble with the cheap noses, Jack.”

Schmitt, it turns out, was basically allergic to the Moon.

Of all the difficulties involved with putting a man on the Moon, “the major issue the Apollo astronauts pointed out was dust, dust, dust,” Larry Taylor, director of the Planetary Geosciences Institute, said in an interview with the Soil Science Society of America. The Apollo 11 astronauts griped that the “particles covered everything and a stain remained even after our best attempts to brush it off.” An Apollo 12 crew member moaned that the lunar module “had so much dust that when I took my helmet off, I was almost blinded.”

Moondust may look soft and pillowy, but it’s actually sharp and abrasive, largely the detritus of micrometeorite impacts. With no wind or moving water on the Moon’s surface, moondust never erodes. Effectively, no natural process exists on the lunar surface that can round its edges. When astronauts inhale what is essentially finely powdered glass, it becomes a huge health hazard [PDF]: The powder is so jagged that a deep breath could cause it to lodge in the lungs and pierce the alveolar sacs and ducts [PDF], resulting in a lunar version of “stone-grinder’s disease,” or silicosis, a deadly condition that commonly killed coal miners (and still kills 100 Americans a year). To complicate…

See What Titan, Saturn’s Largest Moon Looks Like

In 2005, the European Space Agency’s Huygens probe—which had been sent into space with its mothership, NASA’s Cassini spacecraft, to learn more about Saturn and its moons—became the first spacecraft to land on an object in the outer solar system. That object was Titan, a hazy, planet-like moon of Saturn. Now, 12 years after the historic voyage, Mashable reports that NASA has released a video of Huygens’s descent.

Huygens took samples of Titan’s atmosphere and captured hundreds of photos of the moon. These images revealed a new, alien world with rugged mountains, dramatic gorges, and dark drainage channels that were suggestive of liquid…

NASA Is Looking to Make a Mobile Water Factory on the Moon

Water has long been the limiting factor for humans in space. But now, NASA is developing a rover that can make water on the Moon. Such a capability will be necessary for any serious attempt at the permanent settlement of Mars, or any other long-term space voyage. If successful, it will inaugurate a new, critical area in space exploration, where resources from other worlds can be harnessed and used.

Presently, everything we use in space is made on Earth. Consider the big, visible parts of human exploration of the solar system, rockets like the Space Launch System (SLS), under construction and set for its maiden voyage in 2018. There’s also the Orion capsule, tested previously and set to fly atop SLS (without astronauts). Then there’s work on habitats: Scientists are currently working on manufacturing artificial habitats for the International Space Station, but soon will be working on one for the Martian surface. A huge part of this kind of pioneering the solar system, however, concerns not just what we bring to other worlds, but what we leave behind. The Lunar Resource Prospector is the first big step in striking that balance.

The real problem of colonization is mass. It’s very expensive to send something to space, and the heavier it is, the more it costs. It takes hundreds of kilograms on the launch pad to put a single kilogram on the surface of Mars, and Martian settlers will need many, many metric tons of commodities to survive. Practically speaking, they can’t take everything they will need from Earth. To colonize the solar system, they will have to learn how to use the resources of the solar system.

The good news is that everything in the solar system is a potential resource for settlers. In-situ resource utilization, or ISRU, is the concept of mining resources on other worlds and turning them into useful commodities, as well as recycling waste created on other worlds. (Waste conversion solves two problems: It creates new useful things and eliminates garbage. The ISS dumps its garbage, allowing it to burn up in the atmosphere. But surface dwellers on Mars won’t have such a convenient disposal service.)

Energy is an important part of ISRU, and from a settlement perspective, energy is very cheap. The Sun is a giant fusion reactor in the sky, after all, and to harness it, all pioneers need are a few solar panels that they bring from home. Those panels will provide energy for a very long time—energy that can be used for ISRU.

Mars is the most likely current spot for future human settlement, so consider what resources might be available there: Settlers could extract oxygen from Mars’s soil, known as regolith. Water could be extracted from volatiles in the soil, essentially baking them off. There is also carbon dioxide in the Martian atmosphere. Combine carbon with electrolyzed water and settlers can make methane, which could be used as fuel.

Settlers won’t need to take building material to Mars; they could easily glue soil together and make bricks. Metals could also be extracted from Martian regolith to build things. Because Mars is rich with carbon, hydrogen, and oxygen, settlers could even make plastic. What would they build first? Probably greenhouses, for starters. Growing crops for food will also be useful for water purification and oxygen generation.


Look Up Again! The Final Supermoon of 2016 Rises Tonight

You might be sick to death of hearing about “supermoons.” If that’s the case, I bring good news: tonight, December 13, you’ll see the final supermoon of 2016. If you’re not sick of them, I also bring good news, because you have one more supermoon to see.

Of course, where there is good news there is bad, and it’s this: The supermoon will make it very difficult to catch the Geminid meteor shower, which peaks tonight. Don’t give up, however; because of the sheer volume of meteors that comprise the Geminids, you might see some shooting across the sky.

Before last year, when the red harvest supermoon took over the world, you might never have heard of a supermoon. And now we’ve had three in a row to close out the year: October’s super hunter’s moon, November’s super beaver moon, and now December’s full cold or long nights supermoon. This is true in part because supermoon is not an astronomy term, but rather, one of astrology. (In case you are wondering about the difference: astronomy is science; astrology is make believe.) The name has stuck of late because it’s Twitter-friendly and a lot easier to remember than the actual name for the phenomenon: perigee-syzygy of the Earth–Moon–Sun system.

If you want to understand what’s going on and why there are so many supermoons recently, you really do need to look at the proper name. Perigee occurs when the Moon is…