ESOcast 38: Faraway Eris is Pluto’s twin

This ESOcast describes how astronomers have accurately measured the diameter of the faraway dwarf planet Eris for the first time by catching it as it passed in front of a faint star. This event was seen at the end of 2010 by telescopes in Chile, including the TRAPPIST telescope at ESO’s La Silla Observatory. The observations show that Eris is an almost perfect twin of Pluto in size. Eris seems to have a very reflective surface, suggesting that it is covered in ice, probably a frozen atmosphere.

More episodes of the ESOcast are also available.

Find out how to view and contribute subtitles for the ESOcast in multiple languages, or translate this video on dotSUB.



Visual design and editing: Martin Kornmesser and Luis Calçada.
Editing: Herbert Zodet.
Web and technical support: Lars Holm Nielsen and Raquel Yumi Shida.
Written by: Mathieu Isidro and Richard Hook.
Narration: Dr. J.
Music: John Dyson (from the album Moonwind) and movetwo.
Footage and photos: ESO, E. Jehin, Nick Risinger ( and José Francisco Salgado (
Directed by: Richard Hook and Herbert Zodet.
Executive producer: Lars Lindberg Christensen.


 ESOcast HD (High Definition - 1280 x 720)
 ESOcast SD (Standard Definition - 640 x 480)

 ESOcast HD (High Definition) in iTunes
 ESOcast SD (Standard Definition) in iTunes

About the Video

Release date:26 October 2011, 19:00
Related releases:eso1142
Related announcements:ann11076
Duration:05m 08s

About the Object

Type:• X - ESOcast



Large QT
76.5 MB


Video Podcast
57.3 MB
Medium MPEG-1
121.5 MB
Medium Flash
64.0 MB


Small Flash
26.9 MB
Small QT
18.6 MB

For Broadcasters

Broadcast SD
1.5 GB


168.5 KB

Also see our