Astronomy Blog
An astronomy blog usually (but not always) based in the UK. Pondering questions such as " Has an Earth-like planet been found? "
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- Tue, 01 May 2007 02:35:00 BST
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- Of telescopes and continents
The May episode of the Jodcast is now out in the wild. Getting everyone in the same place to record it is proving harder and harder and this month we were spread over three continents. The main interview is with Dr Carole Mundell and is about gamma-ray burst (GRB) observations with the Liverpool Telescope. The Liverpool Telescope is fully robotic and has lots of programs and scripts running to automate the rapid observations needed once a GRB alert happens. Apparently she even gets automatic emails and text messages from the telescope in the middle of the night!
We also get Tim joining us over Skype from the European Southern Observatory at La Silla, Chile. It was pretty cool to be able to talk to him whilst he was on the mountain and find out what he was up to. He has let us use some of his photos from the past few days in the May shownotes. I'm very jealous.
Finally, I chose the cover art because it related to the GRB topic and I thought it was pretty interesting. It certainly isn't your traditional pretty picture. - source
Tue, 01 May 2007 02:35:00 BST - Caelumnoctu
Chris Lintott (him of Sky At Night stardom) reports that Asteroid 57424 (or 2001 SP22) has been given the name Caelumnoctu in honour of the long running, British TV series. In case you were wondering about the name, Caelumnoctu comes from the Latin words caelum (sky or heaven but also an obscure southern constellation) and noctu (night). Apparently this was announced at the 50th anniversary party that was held the other night at Patrick Moore's home. Here's to another 50 years!
Aside: I was amused to discover that Technorati thinks there is "Nothing in the known universe tagged Caelumnoctu". Hopefully that situation should change now. - source
Fri, 27 Apr 2007 00:48:00 BST - Earth-like planet found?
I'm just reading a European Southern Observatory press release about a potential planet that is 1.5 times the diameter of the Earth and five times the mass. There are some things about it that are niggling me so I'll write more when I've actually read the paper that the discoverers are planning to submit as a Letter to Astronomy and; Astrophysics. In the mean time, the Bad Astronomer and News in Space (MP3: 32.6 MB) have their takes on the news.
Update (11:50 BST): I've now read the paper which hasn't been accepted yet (that doesn't mean it won't be!). One of the things in the press release that concerned me was the statement that the radius of the planet was 1.5 that of the Earth. The reason for my concern is that this planet (and the others around the same red dwarf star) were found using the radial velocity method whereby the changes in velocity of the parent star are monitored. This method can only tell you the periods of planets around the star. However, using the period, the size of the change in velocity, and Kepler's laws you can work out the mass and size of the orbit. This still doesn't give you the physical size of the planet. To do that you either need the planet to pass infront of its parent star or to know the composition (rocky, gas etc) and make a guesstimate at the size from mass and density. In this case, the authors have relied on a paper by Valencia et al (2006) which makes various assumptions to get a relationship between the mass of 'super-Earths' and their sizes. So the 1.5 Earth-diameter figure relies on this model being valid for a planet forming near a red dwarf star. It may be fine but I'd like to wait to see.
The other thing I'm slightly confused over are the final masses (why no uncertainties on these?). The quoted masses seem to be the minimum masses that the planets could have and the true mass depends on the inclination of the orbital planes. So, they could be larger. Having said all this, it is good to see that the authors have considered other possibilities to explain their data. For instance, they considered large sunspots on the star. In the end they dismiss these because other measurements show the star to be quite inactive. - source
Wed, 25 Apr 2007 10:42:00 BST - Wow!
The Hubble Space Telescope is celebrating 17 years of operations with a truly fantastic image of the Carina nebula. Take a look (click image for larger versions)!The full size image totally blew me away but it gets even better when you zoom in and have a look at the star clusters, Bok globules, star formation regions and shocks. I could spend hours looking around this image just exclaiming at the shear beauty of it and finding gems. The full sized image is a mosaic created from 48 separate images taken by the Advanced Camera for Surveys - which broke at the end of January - and consists of a whopping 29,566 x 14,321 pixels. It covers a region about 50 light years across and is false colour; red represents sulphur, green shows the hydrogen and blue is the oxygen. Watch the latest Hubblecast video for more details.
Hubble Space Telescope view of the Carina Nebula which is 7500 light years away. Image composed of 48 frames from the ACS. Red is sulphur, green is hydrogen and blue is oxygen. CREDIT: NASA, ESA, N. Smith (University of California, Berkeley), and The Hubble Heritage Team (STScI/AURA)
I have tried printing out a lower resolution version (although still huge) but the printer I used washes out the colours so it looks as if I have spilt water all over it. I would love to see this wall-sized from a good printer. Anyway, here are a few close-ups.
Caring nebula close-up CREDIT: NASA, ESA, N. Smith (University of California, Berkeley), and The Hubble Heritage Team (STScI/AURA)The image above shows a close-up of one region containing an open cluster with Bok globules looking amazing silhouetted against the rest of the nebula. Another area of the full image (below) shows the star Eta Carina (bottom right) itself with its two lobes of material that it ejected around 150 years ago. The area next to it looks pretty circular and I can't help think that it is some kind of shock front from another star.
Caring nebula close-up CREDIT: NASA, ESA, N. Smith (University of California, Berkeley), and The Hubble Heritage Team (STScI/AURA)There is a huge amount of really interesting physics going on in this image but, for now, I'm just going to sit and be awed.
Caring nebula close-up CREDIT: NASA, ESA, N. Smith (University of California, Berkeley), and The Hubble Heritage Team (STScI/AURA)
- source
Tue, 24 Apr 2007 14:00:00 BST - Cheap binoculars
This is just a heads up for people in the UK. Via a friend I have discovered that the LIDL chain of supermarkets is currently selling Bresser (part of Meade) 10x50 binoculars for 10 of your Earth pounds. For only ;10 they are really good and worth getting (I've just bought a pair) but I suspect they may sell out pretty quickly. - source
Tue, 24 Apr 2007 12:30:00 BST - Is Zeus a planet?
In case you were on another spherical object last summer, you were probably aware of the debate over the definition of a planet. In this debate, Pluto has been seen widely to have been "demoted" to dwarf planet status. The word "demoted" has been used often as if Pluto has stopped existing or has had its pension rights removed. Before the debate I was quite happy for Pluto to remain a planet and even admit some new members to the the planet club based on a definition such as "spherical equilibrium". However, the ensuing debate and the apparent emotional response has left me caring very little about what is and what isn't a planet. Ultimately, this is an issue of semantics and doesn't affect the reality of what Pluto, Eris, Earth or Jupiter are actually composed of or how interesting they are.
One of the things that has come out of all this is the emotional attachment, anger and upset that many people have over Pluto (I can't help thinking that there are far more important things for people to worry about on Earth than what we call Pluto). Perhaps some of the attachment to Pluto is due to the name. After all, Disney was quick to use the name for a popular cartoon dog and that must be built into the conciousness of many people in the western world. What if Pluto was not named Pluto? What if Venetia Phair had been ignored and some of the original suggestions had been used? Would we have a Society for the Preservation of Zeus as a Planet? Would anybody start a petition to save 134340? Would New Mexico have made a declaration that Constance is a Planet when over its skies? Does alliteration help Pluto's cause? Can I ask any more rhetorical questions?
Pluto and its three moons are hugely interesting. I no longer care if it is a planet or dwarf planet. It is Pluto. - source
Tue, 24 Apr 2007 12:21:00 BST - AGILE launched!
I hear that the Italian space mission AGILE was successfully launched from India at 12:00 CEST. AGILE (I think this is pronounced a-jee-lay) is an X-ray and gamma-ray imaging spacecraft which is considered to be like a bigger version of EGRET or a smaller version of NASA's GLAST spacecraft (due for launch no earlier than December this year). Buona fortuna AGILE. - source
Mon, 23 Apr 2007 16:09:00 BST - NAM 2007 in the pod
I've already excused my lack of blog posts from the National Astronomy Meeting and the reason has partly been the time (and effort) I've put in to podcasting the week. Days one to four are now online in special daily shows.
We covered a huge range of topics including: International Heliophysical Year (Lucie Green), meteorites (Monica Grady), wakes left by moving stars (Chris Wareing), the effects of solar radiation on astronauts (Mike Lockwood), magnetic bubbles/force-fields (Ruth Bamford), the Herschel Telescope (Matt Griffin), the Hubble Space Telescope and World Space Observatory (Martin Barstow), astro-chemistry and the Sky At Night (Chris Lintott) and exoplanets (Peter Wheatley). The final day (day 5 which was today) will be released tomorrow and contains interviews about STEREO (Chris Davis), Mars Express (Helen Walker) and RS Ophiuchi (Mike Bode).
Some of the interviews were recorded in the University of Central Lancashire's recording studios and others were recorded in the lecture theatres, corridors and poster sessions. Personally, I like to have some of the background noise because it puts across some of the feel of the conference. Thanks to David Boyce, Paul Steele and Neil Phillips who joined the standard Jodcast crew to help with presenting duty and get a broader view of the many parallel sessions. - source
Fri, 20 Apr 2007 22:43:00 BST
