Planet at Alpha Centauri found

I'd like to know why they have just found a planet at Alpha Centauri,
our nearest star, when they have been searching the skies for years
and have found 600 or so planets (iirc). it must've been the first
place they looked, mustn't it? Strikes me as odd.

Dear Jack:

On Wednesday, October 17, 2012 11:20:08 AM UTC-7, wrote:
....
I'd like to know why they have just found a
planet at Alpha Centauri, our nearest star,

Not the nearest, just "very near".

when they have been searching the skies for
years and have found 600 or so planets (iirc).
it must've been the first place they looked,
mustn't it? Strikes me as odd.

There are 3 or 4 methods involved, and only recently have they become more accurate.

If the Earth is very near the stellar systems's ecliptic plane, then we have a much better chance of detection (regardless of method).

If the planet is massive, we have another very good chance of detection.

Beyond this, we didn't even know for sure there was a massive object in trojan with the Earth until very recently, and we had no idea Pluto had at least 5 moons until we went out there.

Not really that odd, that you don't know what is what, until you really start looking... then sharpen your tools, and look some more. Who is paying money to know these things, because the instrumentation isn't free, and there is significant time involved in analysis?

David A. Smith

In article ,
writes:
I'd like to know why they have just found a planet at Alpha Centauri,
our nearest star, when they have been searching the skies for years
and have found 600 or so planets (iirc).

It's a very difficult observation; it took 459 separate observations
over 3.5 years on a big telescope with a very impressive modern
instrument. Plus extremely complex data reduction, removing many
effects much larger than the planet signal. The final velocity
signal is only half a meter per second! What surprises me is that
the planet was detected at all, not how long it's taken.

The scientific paper is at
http://www.nature.com/nature/journal...ture11572.html
but you'll need a subscription or to pay to read it. The press
release, which excellent, is at
http://www.eso.org/public/news/eso1241/

The press release has a link to what appears to be the scientific
paper minus Nature's editing and minus the Supplementary Information
at
http://www.eso.org/public/archives/r...1/eso1241a.pdf

Phil Plait's excellent blog, which shows the plot of the key data,
is at
http://blogs.discovermagazine.com/ba...-has-a-planet/

Nature's commentary on the discovery, also pay or subscription, is at
http://www.nature.com/nature/journal...ture11636.html
(I wouldn't pay for this, but it's worth reading if you have a
subscription. Among other things, it points out that because the
analysis is so tricky, the discovery needs to be confirmed by other
methods before being 100% accepted.)

--
Help keep our newsgroup healthy; please don't feed the trolls.
Steve Willner Phone 617-495-7123
Cambridge, MA 02138 USA

On 17/10/2012 2:20 PM, wrote:
I'd like to know why they have just found a planet at Alpha Centauri,
our nearest star, when they have been searching the skies for years
and have found 600 or so planets (iirc). it must've been the first
place they looked, mustn't it? Strikes me as odd.

Most of the 1000's of exoplanets found so far have been discovered by
Kepler. Kepler only looks for planets by the Transit Method, which when
you get right down to it, is the easiest method of detecting planets.
Before Kepler, we used the Wobble Method. The Wobble Method uses Doppler
shifts to determine if a planet is tugging on a star. It works really
well when the planets are really massive and/or very close in to their
stars. Smaller planets are harder to detect using this method. We
couldn't use the Transit Method like with Kepler because this star
system doesn't seem to be aligned to our line of sight. Also Kepler
probably doesn't even point in the direction of this star system.

So our only hope was to find a planet with the Wobble method, which as I
said before, is better at detecting Big planets. But they've refined the
Wobble Method, and it can detect far smaller planets now. It's much
harder to detect planets with the Wobble method, but it can detect
planets that aren't perfectly aligned with our line of sight.

Yousuf Khan

Yousuf Khan wrote:
On 17/10/2012 2:20 PM, wrote:
I'd like to know why they have just found a planet at Alpha Centauri,
our nearest star, when they have been searching the skies for years
and have found 600 or so planets (iirc). it must've been the first
place they looked, mustn't it? Strikes me as odd.

Most of the 1000's of exoplanets found so far have been discovered by
Kepler. Kepler only looks for planets by the Transit Method, which
when you get right down to it, is the easiest method of detecting
planets. Before Kepler, we used the Wobble Method. The Wobble Method
uses Doppler shifts to determine if a planet is tugging on a star. It
works really well when the planets are really massive and/or very
close in to their stars. Smaller planets are harder to detect using
this method. We couldn't use the Transit Method like with Kepler
because this star system doesn't seem to be aligned to our line of
sight. Also Kepler probably doesn't even point in the direction of
this star system.

True, Kepler is scanning only a small portion of the sky in the northern
Milky Way, in (IIRC) Cygnus.


So our only hope was to find a planet with the Wobble method, which
as I said before, is better at detecting Big planets. But they've
refined the Wobble Method, and it can detect far smaller planets now.
It's much harder to detect planets with the Wobble method, but it can
detect planets that aren't perfectly aligned with our line of sight.

Yousuf Khan

--
Mike Dworetsky

(Remove pants sp*mbl*ck to reply)

dlzc wrote:
Beyond this, we didn't even know for sure there was a massive object in trojan with
the Earth until very recently, and we had no idea Pluto had at least 5 moons until we
went out there.

Nix, Hydra and "P5" were discovered using Hubble. New Horizons won't
get to Pluto until July 2015.

-- Bill Owen

On Oct 17, 1:33*pm, (Steve Willner) wrote:

Help keep our newsgroup healthy; please don't feed the trolls.
Steve Willner * * * * * *Phone 617-495-7123 * *
Cambridge, MA 02138 USA

So, here we have guys from Harvard and JPL and they are standing on a
planet with a specific set of values for size and rotational speeds
yet these highly paid individuals can't come to terms with the basic
facts of our own planet and specifically the maximum equatorial speed
of 1037.5 miles per hour or for 15 degrees of rotation -

http://imagine.gsfc.nasa.gov/docs/as...s/970401c.html

It is astonishing that they cannot follow the dictates of the 24 hour
AM/PM system and the Lat/Long system which determines that our
planet,do you hear,our planet turns at a rate of 15 degrees per hour
as an assertion derived through very specific references and none of
which involve VLBI and a rotating celestial sphere of Ra/Dec.

Never has the world witnessed such a scam and a very expensive one
that has brought all science into disrepute.

In sci.astro message 8fa74149-e333-408a-a87c-ef173497a4e0@googlegroups.
com, Wed, 17 Oct 2012 13:06:52, dlzc posted:


Beyond this, we didn't even know for sure there was a massive object
in trojan with the Earth until very recently, and we had no idea Pluto
had at least 5 moons until we went out there.

Going part-way out there did not make it possible to find them, except
in so far as the intention of going past there makes it desirable to
look for such. "We" have not yet gone to Pluto, though New Horizons can
no longer avoid the Plutonic region.

--
(c) John Stockton, nr London, UK. Mail via homepage. Turnpike v6.05 MIME.
Web http://www.merlyn.demon.co.uk/ - FAQqish topics, acronyms and links;
Astro stuff via astron-1.htm, gravity0.htm ; quotings.htm, pascal.htm, etc.
No Encoding. Quotes before replies. Snip well. Write clearly. Don't Mail News.

On Oct 17, 11:20*am, wrote:
I'd like to know why they have just found a planet at Alpha Centauri,
our nearest star, when they have been searching the skies for years
and have found 600 or so planets (iirc). it must've been the first
place they looked, mustn't it? Strikes me as odd.

Perhaps it was simply too obvious, something like Guth-Venus as been
for more than a dozen years.

“GuthVenus” 1:1, plus 10x resample/enlargement of the area in
question:
https://picasaweb.google.com/1027362...79402364691314

http://groups.google.com/groups/search
http://translate.google.com/#
Brad Guth,Brad_Guth,Brad.Guth,BradGuth,BG,Guth Usenet/”Guth Venus”