Jonathan Crowe

I’m a blogger and writer from Shawville, Quebec. I blog about maps at The Map Room, review books for AE: The Canadian Science Fiction Review, and edit a fanzine called Ecdysis. More about me.

My Correct Views on Everything
↳ Astronomy & Space

Proxima Centauri Has a Planet

Proxima Centauri b
Artist’s impression of Proxima Centauri b (ESO/M. Kornmesser).

Proxima Centauri, the star nearest to our sun, has a planet in its habitable zone.

Today researchers published an article in Nature describing the planet as “a small planet with a minimum mass of about 1.3 Earth masses orbiting Proxima with a period of approximately 11.2 days at a semi-major-axis distance of around 0.05 astronomical units. Its equilibrium temperature is within the range where water could be liquid on its surface.” (Proxima is a red dwarf. Its habitable zone is really close in.)

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Ceres’ Bright Spots Are Carbonates

Occator Crater and Carbonates

We now have some idea of what those bright spots on the surface of Ceres are. In an article published last month in Nature, scientists report that the spots’ spectral readings are consistent with sodium carbonate. (They had initially been thought to be made up of hydrated magnesium sulfate.) Sodium carbonate suggests the existence of subsurface water or ice that was brought to the surface by an impact (the bright spots are all in impact craters; the brightest are found in Occator, a crater 92 km wide); the carbonates would have been left behind after the water boiled off. JPL, Scientific American.


Previously: A Closer Look at Ceres’ Bright Spots.

Would You Just Look at Charon


Pluto’s largest moon, Charon, is at least as interesting as its parent planet, if this enhanced-colour high-resolution photo from the New Horizons flyby, released last Thursday, is any indication. With vastly different terrains to the north and south of a giant canyon at least 1,600 kilometres long (Charon’s diameter is only 1,214 km), Charon looks like someone took two completely different hemispheres and bashed them together with great force. Or a hard-boiled egg that wasn’t peeled very well. Image credit: NASA /JHUAPL/SwRI.

More Maps of Ceres

False colour compositional map of Ceres

New maps of Ceres were released today at the European Planetary Science Conference in Nantes, France. One is a colour-coded topopgraphical map that resembles a map we saw earlier but adds newly approved names for topographical features. Another, the false-colour map seen above, combines imagery through infrared, red and blue filters and highlights compositional differences on Ceres’ surface (different materials reflect light at different frequencies). Image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA.

Previously: New Maps of Ceres and Pluto; Space Maps: Ceres, Mars, Exoplanets; At Ceres.

Pluto, Backlit


The New Horizons probe has resumed sending data from its flyby of Pluto and Charon last July. Those of us who are not scientists are mainly interested in the awesome space pics, and last week we got some fine ones: images taken from 15 minutes after the probe’s flyby, looking back on Pluto from an oblique, backlit angle. They show us rugged mountains casting long shadows, and reveal layers in Pluto’s atmosphere. The technical term for this is “holy shit.” Image credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute. (NASA/JHUAPL)

A Closer Look at Ceres’ Bright Spots

Occator Crater on Ceres

We still don’t know what the bright spots on Ceres are, but at least we’re getting a better look at them. Check out this image of Occator Crater: “Because these spots are so much brighter than the rest of Ceres’ surface, the Dawn team combined two different images into a single composite view — one properly exposed for the bright spots, and one for the surrounding surface.” Image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA.

New Maps of Ceres and Pluto

Global Map of Pluto

As I predicted, a new global map of Pluto has been released that incorporates the imagery that has been downlinked so far from the New Horizons flyby: with gridlines, without gridlines. If nothing else, the equatorial projection demonstrates how much of Pluto’s surface was not seen during the very brief encounter. From what I understand, imagery downlinks will resume in September and carry on for another year, so this map will almost certainly see many more updates.

Meanwhile, Ceres also has some new maps.

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The Best Map of Pluto Ever (Until Some Time Later This Month)

New Horizons Map of Pluto

The New Horizons spacecraft’s rendezvous with Pluto is next week, folks, but we’re already getting better views of our favourite dwarf planet than we’ve ever had before. NASA has assembled images taken between June 27 and July 3 into the above map, which despite its relatively low resolution shows some intriguing surface features: the so-called “whale” and “donut.” (Of course, low resolution is relative: this is already much better than the Hubble-based maps of Pluto released in 2005 and 2010.) Image credit: NASA-JHUAPL-SWRI.

Approaching Ceres


The Dawn spacecraft’s trajectory is slowly edging it closer to Ceres. This is one of a series of images of Ceres taken between April 24 and 25 from a distance of 8,500 kilometres. Image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA.

Previously: At Ceres.

New Moon Maps

Topographic Map of the Moon (Hare et al.)

Two stunning maps of the Moon have been released by the USGS, both based on data collected by the Lunar Reconnaissance Orbiter: one an image mosaic assembled from visual imagery, the other (above) a colour-coded topographical map derived from laser altimeter data. Via io9.

Space Maps: Ceres, Mars, Exoplanets

Mars: Ares Vallis

A Cometary Closeup

Mosaic of 67P/Churyumov-Gerasimenko from Rosetta spacecraft

Last Saturday, the Rosetta spacecraft passed within 14 kilometres of the surface of Comet 67P/Churyumov-Gerasimenko. The above mosaic was assembled from imagery taken from an altitude of 19.9 kilometres, and depicts the comet’s Imhotep region. (Here’s a map of Churyumov-Gerasimenko’s named regions. We’re mapping the surfaces of comets now. Let that sink in.) Image credit: ESA/Rosetta/NAVCAM (CC licence).

At Ceres

Ceres in Half Shadow

As of today the Dawn spacecraft is now in orbit of Ceres. Because Dawn’s trajectory puts it in the dwarf planet’s shadow, it’ll be the middle of next month before se start seeing better-resolution images than we’ve seen so far as it approached. The above images were taken from 40,000 km away on February 25.

Meanwhile, early images of Ceres have already been assembled into a preliminary equirectangular mosaic:

Ceres (mosaic)

No labels yet, because nothing’s been named yet: this is the first time we’ve seen these features. But Gazeteer of Planetary Nomenclature says that, in keeping with Ceres’ origin as the name for the Roman goddess of agriculture, Ceres’ craters will be named for “[g]ods and goddesses of agriculture and vegetation from world mythology”; other features will be named for agricultural festivals.



A newly reprocessed view of Jupiter’s moon Europa, based on images from the Galileo mission, has been released. “To create this new version, the images were assembled into a realistic color view of the surface that approximates how Europa would appear to the human eye.” Image credit: NASA/JPL-Caltech/SETI Institute.

Geologic Maps of Vesta

Geologic map of Vesta

Geologic maps of Vesta, the asteroid visited by the Dawn spacecraft between July 2011 and September 2012, have been produced for a special issue of the planetary science journal Icarus. Above, a global geologic map of Vesta, compiled from 15 individual quad maps and using a Mollweide projection (Vesta itself is decidedly non-spheroid, but still). Image credit: NASA/JPL-Caltech/ASU.

Previously: Atlas of Vesta.

Moon and Comet Maps

OSIRIS map of Comet 67P/Churyumov-GerasimenkoTopography of Earth's moon

Maps of planets, moons and other objects in our solar system always get me excited, though truth be told they were among the less popular posts on my old Map Room blog. Here are a couple of rather colourful recent examples:

Image credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA (above left); NASA/Colorado School of Mines/MIT/GSFC/Scientific Visualization Studio (above right).

Geologic Map of Mars

Geologic Map of Mars

As I said during the Q&A part of my fantasy maps presentation at Readercon (see previous entry), maps of other worlds in the solar system are usually images from space probes that have been set to a map projection. The key word is usually. On Monday the U.S. Geological Survey released a geologic map of Mars that “brings together observations and scientific findings from four orbiting spacecraft that have been acquiring data for more than 16 years.” Via io9 and Wired.

Astronomy in the Pontiac

Whatever the quality of the Pontiac’s roads, its skies are very good for astronomical observing — especially when you consider how close we are to Ottawa. From my backyard, which is not well shielded from porch and street lighting, I’ve gotten magnitude-five views with the naked eye — suffice to say, the Milky Way is in fine form during the summer. (Clouds are a wrinkle, though: they never fail to turn up during neato ephemeral events.)

In that vein I note with interest a group called AstroPontiac, and its Indiegogo campaign to raise funds to buy a roll-off roof observatory and a couple of telescopes. They’re trying to raise $12,500, which seems modest, but their goal of providing a site for amateur observing is fairly low-cost, considering. Ottawa Citizen coverage.

Ganymede and Mercury

Geologic map of Ganymede

The USGS has published a geologic map of Ganymede, Jupiter’s largest moon and the largest moon in the Solar System, based on imagery from the Voyager 1, Voyager 2 and Galileo probes. Via Centauri Dreams, Sky and Telescope.

Meanwhile, Sky and Telescope has produced a Mercury globe based on MESSENGER imagery. They already produce both visual and topographic globes of the Moon and Mars, as well as a globe of Venus coloured for elevation. (I’m crossing my fingers for globes of the outer moons, myself.)

I’m big on maps and globes of the rest of the Solar System. Recent entries: Maps of Mercury; Atlas of Vesta; A Topographic Map of Titan.

Ceres and a Supernova

Supernova in M 82 Today was a good day on the astronomy front. Data from the Herschel space observatory has revealed the presence of water vapour around Ceres, the largest object in the asteroid belt (this is even more cause to look forward to the arrival of the Dawn spacecraft there next year). And a supernova has been detected in M82, a galaxy close enough and bright enough to be seen through amateur telescopes (I’ve done so on more than one occasion). So: lots of awesome. (Photo credit: UCL/University of London Observatory/Steve Fossey/Ben Cooke/Guy Pollack/Matthew Wilde/Thomas Wright.)

Maps of Mercury

H-12 Michaelangelo

The USGS has released quad maps of the planet Mercury as a set of PDF files: “The 1:5 million-scale series of Mercury maps divides Mercury into 15 quadrangles, H-1 through H-15 (five Mercator, eight Lambert Conformal, and two Polar Stereographic quadrangles). The base mosaic was produced with orbital images by the MESSENGER Team and released by NASA’s Planetary Data System on March 8, 2013. This new global mosaic includes 100% coverage of Mercury’s surface.”

Proxima Centauri

Proxima Centauri

At 4.24 light years away — only 40 trillion kilometres! — Proxima Centauri is the second-closest star (after the Sun, of course). Even so, most people have never seen it, because it’s ridiculously hard to see. Due to its position in the sky it cannot be seen north of 27� N latitude, and even then you need a telescope because even the closest red dwarf cannot be seen with the naked eye. And even through the telescope I don’t think Proxima stands out from the rest of the starfield. (“Which pinpoint is it? This one? Oh. That’s nice.”) But! The Hubble to the rescue! Here it is, in red and infrared light. Image credit: ESA/Hubble & NASA.

Gordan Ugarkovic


Croatian software developer Gordan Ugarkovi? plays with NASA imagery in his spare time, processing colour composites from raw data, mostly from the Cassini mission. The results are stunning, and can be seen on his Flickr photostream. His latest, a jaw-dropping wide-angle mosaic of Saturn, is getting all sorts of raves. Image credit: NASA/JPL/SSI/Gordan Ugarkovi?.

Atlas of Vesta

Atlas of Vesta

An atlas of Vesta, comprising a series of 29 quad maps (mirror) assembling visual and relief data from the Dawn spacecraft’s visit to the large asteroid between July 2011 and September 2012, has been released.

Andromeda through the Subaru Telescope

Andromeda Galaxy (M31), Subaru telescope

The above image is not the best picture of the Andromeda Galaxy ever taken, not by a long shot. It is, however, a significant one. It’s a test image taken by the 8.2-metre Subaru Telescope’s Hyper-Suprime Cam, an 870-megapixel, three-ton imager mounted on the telescope’s f/2 primary focus. Which is to say that it produces absurdly high-resolution images (here’s a 35-megapixel, 6000×5957 version).

But what raised my eyebrows and dropped my jaw was the field of view: 1.5 degrees of sky is just preposterous on a telescope with a 15-metre focal length. This image of the Andromeda Galaxy was taken in a single shot. How do I explain how freaky that is? My 80-mm refractor, with its 500-mm focal length, could get the entire Andromeda Galaxy in the eyepiece, but not my larger scopes. Most amateur photography of this galaxy involves photographing pieces of the galaxy (in, say, a 2×3 grid) and assembled into a final mosaic. A single shot on a telescope that size? The mind boggles.

Pluto’s Problematic Cartography

We’re still two years from the New Horizons flyby of Pluto, but the cartography of the solar system’s most famous dwarf planet — based on Hubble imagery — is already several kinds of problematic, as Emily Lakdawalla explains in a post that also explains how the cartography of other worlds is done. (Key challenges include defining the north and south pole — which one is which? — as well as a prime meridian.)

Solstice CME

Sun Emits a Solstice CME

The Sun marked the solstice with this coronal mass ejection. Full-disk view. The Sun laughs at your puny fireworks. Image credit: NASA/SDO.

IC 2944

The Very Large Telescope Snaps a Stellar Nursery and Celebrates Fifteen Years of Operations

The European Southern Observatory, one of my favourite sources of open-licence astrophotography, marked the 15th anniversary of its Very Large Telescope by releasing this new image of IC 2944, a stellar nursery some 6,500 light years away in the constellation Centaurus. The picture combines visible light with narrowband hydrogen-alpha and oxygen-III emissions. Check out all the Bok globules! Image credit: ESO.

The Ring Nebula

Ring Nebula (M57)

Today a new Hubble image was released that promises “the most detailed observations ever” of the Ring Nebula (Messier 57), a planetary nebula about 2,300 light years away. It’s easily spotted in backyard telescopes (I’ve seen it many times myself). This image, taken through a combination of regular red, green and blue filters along with narrowband filters that reveal specific emissions, is good enough to form the basis of a 3D model. And if that’s not enough Ring Nebula for you, here’s another image combining Hubble narrowband data with ground-based infrared observations that reveals the nebula’s outer halo. Image credit: NASA, ESA, and the Hubble Heritage (STScI/AURA)-ESA/Hubble Collaboration.

A Topographic Map of Titan

Global topographic map of Titan (NASA/JPL-Caltech/ASI/JHUAPL/Cornell/Weizmann)

The Cassini team has released a global topographic map of Saturn’s moon Titan. What makes this map interesting is the fact that, due to its thick atmosphere, Titan can only be mapped by radar during Cassini’s close flybys. As a result, only half of its surface has been imaged, and only 11 percent has topography data. For this map, the remainder was, well, extrapolated:

Lorenz’s team used a mathematical process called splining — effectively using smooth, curved surfaces to “join” the areas between grids of existing data. “You can take a spot where there is no data, look how close it is to the nearest data, and use various approaches of averaging and estimating to calculate your best guess,” he said. “If you pick a point, and all the nearby points are high altitude, you’d need a special reason for thinking that point would be lower. We’re mathematically papering over the gaps in our coverage.”

Topo maps of parts of Titan have been released before, but not for the entire moon. See previous posts on The Map Room: Titan in Stereo; Topography of Titan.

Image credit: NASA/JPL-Caltech/ASI/JHUAPL/Cornell/Weizmann.

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