Feeds

Sedna shrinks after new measurement

Trans-Neptunian object way smaller than Pluto may carry water ice

Application security programs and practises

Dwarf planet wannabe Sedna is considerably smaller than previously assumed, according to a new study of Trans-Neptunian Objects (TNOs).

Once the most distant object observed in the solar system, Sedna was thought to have a diameter of around 1700km. But a new paper, dubbed "TNOs are Cool": A survey of the trans-Neptunian region” suggests the object has a diameter of just 995±80 km.

This estimate comes from new data drawn from Photodetector Array Camera and Spectrometer (PACS) on the European Space Agency's Herschel Space Observatory. The new size estimate was derived by measuring Sedna's predicted rotation period.

The paper says the PACS instrument detected a greater albedo than had previously been measured, suggesting the presence of water ice on the remote rock.

The study also considered the evocatively-named 2010 EK, another TNO that had previously been assumed to have a diameter of about 770km. The new study suggests it is only 470km or so around. No explanation is offered for the more optimistic previous estimates.

It's not hard to imagine that these new measurements will fuel ongoing definition debates about what constitutes a dwarf planet, as previous estimates suggested Sedna was abou 80% the size of Pluto. ®

Build a business case: developing custom apps

More from The Register

next story
Just TWO climate committee MPs contradict IPCC: The two with SCIENCE degrees
'Greenhouse effect is real, but as for the rest of it ...'
BEST BATTERY EVER: All lithium, all the time, plus a dash of carbon nano-stuff
We have found the Holy Grail (of batteries) - boffins
Asteroid's DINO KILLING SPREE just bad luck – boffins
Sauricide WASN'T inevitable, reckon scientists
Flamewars in SPAAACE: cooler fires hint at energy efficiency
Experiment aboard ISS shows we should all chill out for cleaner engines
The Sun took a day off last week and made NO sunspots
Someone needs to get that lazy star cooking again before things get cold around here
Boffins discuss AI space program at hush-hush IARPA confab
IBM, MIT, plenty of others invited to fill Uncle Sam's spy toolchest, but where's Google?
Famous 'Dish' radio telescope to be emptied in budget crisis: CSIRO
Radio astronomy suffering to protect Square Kilometre Array
prev story

Whitepapers

Implementing global e-invoicing with guaranteed legal certainty
Explaining the role local tax compliance plays in successful supply chain management and e-business and how leading global brands are addressing this.
Consolidation: The Foundation for IT Business Transformation
In this whitepaper learn how effective consolidation of IT and business resources can enable multiple, meaningful business benefits.
Application security programs and practises
Follow a few strategies and your organization can gain the full benefits of open source and the cloud without compromising the security of your applications.
How modern custom applications can spur business growth
Learn how to create, deploy and manage custom applications without consuming or expanding the need for scarce, expensive IT resources.
Securing Web Applications Made Simple and Scalable
Learn how automated security testing can provide a simple and scalable way to protect your web applications.