Tag Archives: planet


Did you enjoy that planetary impact simulator I linked to a while back? Did you enjoy it, perhaps, a little too much, and feel that your galactic karma could do with a bit of balancing? Well, what better way to atone for smashing planets to bits than by building new ones, which is exactly what NASA’s Planet Makeover webapp lets you do [via BoingBoing]. A bit of random fun for friday afternoon: adjust planet size, orbital distance, solar type and planetary age, then hit the button and see whether you’ve made a habitable world. [SPOILERS: your odds of doing so are very low. Good afternoon, Professor Drake!]

Not a new idea, of course (I had a serious hankering for a copy of SimEarth back at the start of the nineties, but never got one), but NASA have wisely brought the idea kicking and screaming into the Twentyteens by a) simplifying it and putting it on the web for free and b) using the word EXTREME! in the name.

Blueprint for a Dying Earth: what would happen if the world stopped spinning?

I’m not sure whether I’m a sucker for outlandish “what if?” speculation because I’ve always read science fiction, or whether I read sf because I have some innate speculative itch that I need to scratch. Whichever it may be, this is the sort of thing that pushes a whole lot of my buttons: using modelling software to determine what Planet Earth would look like were it to – for some reason – stop spinning [via BoingBoing].

The lack of the centrifugal effect would result in the gravity of the earth being the only significant force controlling the extent of the oceans. Prominent celestial bodies such as the moon and sun would also play a role, but because of their distance from the earth, their impact on the extent of global oceans would be negligible.

If the earth’s gravity alone was responsible for creating a new geography, the huge bulge of oceanic water—which is now about 8 km high at the equator—would migrate to where a stationary earth’s gravity would be the strongest. This bulge is attributed to the centrifugal effect of earth’s spinning with a linear speed of 1,667 km/hour at the equator. The existing equatorial water bulge also inflates the ellipsoidal shape of the globe itself.


Today, all three world oceans are connected. This creates a global ocean with basically one sea level. As a consequence of rotational slowdown, the outline of the global ocean would continuously undergo dramatic changes. Equatorial waters would move toward polar areas, initially causing a significant reduction in depth while filling the polar basins that have much less capacity. As regions at high latitude in the northern hemisphere become submerged, the areal extent of the northern circumpolar ocean would rapidly expand, covering the vast lowlands of Siberia and northern portions of North America. The global ocean would remain one unit until the rotation of the earth decreased to the speed at which ocean separation would occur. The interaction between the inertia of huge water bodies and decreasing centrifugal force would be very complicated. As the consequence of steady slowdown of earth’s rotation, the global ocean would be gradually separated into two oceans…

Sure, so it’s pretty unlikely to ever happen… and if it did, speculating about topography would be the last of our concerns, I imagine.

But what if…?

[ As a side note, that’s a great way to virally advertise a piece of software that would otherwise only be of interest to 0.001% of the world’s population. Kudos! ]

Pluto has a posse

Pluto and its moonsIf you’re among the body of people who decried the demotion of poor little Pluto, take heart – it (he?) may end up reinstated some time soon:

If Pluto is reinstated, it will probably be thanks to discovery rather than debate. Mark Sykes of the Planetary Science Institute in Tucson, Arizona, believes that revelations within and beyond our solar system over the coming years will make the IAU’s controversial definition of a planet untenable. “We are in the midst of a conceptual revolution,” he says. “We are shaking off the last vestiges of the mythological view of planets as special objects in the sky – and the idea that there has to be a small number of them because they’re special.”

Sykes believes that missions currently en route to Pluto and the asteroid Ceres, which orbits the sun between Mars and Jupiter, will reveal these dwarf planets as active and intricate worlds. Meanwhile, astronomers may find distant objects as large as Earth which the IAU would not define as planets.

Sykes is among those who prefer a simple and inclusive definition of planet status: if an object is big enough for its own gravity to squeeze it into a rounded shape, then call it a planet. That would make a planet of Pluto again, as well as Ceres and a growing number of other bodies.

All this debate around nomenclature just goes to point out that we’ve a lot still to learn about our own backyard – and that the pace of discovery is picking up. I’m hoping the public interest in space doesn’t fade out after the Moon landing anniversary; even if we can’t go to these places ourselves, I think it’s important for us to think and learn about the universe beyond our gravity well. [image courtesy NASA]

First image of Mercury from Messenger mission transmitted

The first images ever of this side of the first planetMessenger, a NASA probe launched towards Mercury, has transmitted the first image of the unseen side of the first planet in our solar system, Mercury. Whilst Mariner 10 did pass Mercury 3 times in the seventies, it never saw this side due to the strange relationship between Mercury’s spin and orbit around the sun. The image is very good quality, with a lighter region in the top right corner believed to be the area of the planet that comes closest to the scorching heat of the sun.

[via Bad Astronomy Blog, picture by NASA]