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New Brain Teaser Solutions Offered January 5, 2000!
http://oposite.stsci.edu/pubinfo/pr/1999/04/
See SN1987A at center of
photo of Large Magellanic Cloud above
(click on photo for high
res jpeg).
February 23,1987 a rather unprincely star formerly known as Sunduleak in the Large Magellanic Cloud (LMC*, visible from the southern hemisphere only) was observed here on earth to have exploded or "supernovaed" The supernova is now known as SN1987a. (Okay, so astronomers don't always come up with the most imaginative names.) This exploded star is about 170,000 light years from earth. Shown below are before and after pictures. In the left photo is the Tarantula nebula in the LMC, with an arrow pointing to the unexploded star. The photo on the right shows the same region two months after it exploded. The photo below these show in closeup the supernova as it appears now. This was a very dramatic event in history. The only other such event in recent times was the supernova in AD 1054 which left us the Crab Nebula in the Tarus constellation. That event was so bright it was visible in the daytime sky according to Chinese astronomers of the time.
(*The LMC is part of our local group associated with the Milky Way Galaxy.)
Before and After shots below.
- 
David
Mahlin / Anglo-Australian Observatory
- 
HST Photograph (STSI)
STSI
on Novas and SuperNovas (SN1987a and more!)
The starlight from Sanduleak carries a "message" or picture of an event that happened in history, as the progression of core photos shows. The message (the light) only arrived here on earth in 1987, but for it to have travelled from the star to earth took about 170,000 (51.4 ± 1.2 kpc, or ~168,000, see refs and abstract below) years travelling at 186,000 miles per second. Up until 1987 we could see a star at this position and distance. But now we see that no star has been there for the past 170,000 years -- since it exploded 170,000 years ago, or 170,000 light years away.
Brain
Teaser
If the universe is not
at least 170,000 years old, how could that be?
God
made the starlight in route?
The
star isn't really that far away?
Astronomers
are deceived by Satan and/or God?
What
about Russell Humphries'
"rapid
expansion, bounded universe, time dialation"
proposed
in his Starlight and Time book?
If
God fooled us before 1987, why not an appearance of age for creation?
Suggest
Other Ideas
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================================
See
a college astronomy homework assignment to determine distance to SN1987A
(Univ. of Colorada)
Also an abstract from:
The Magellan Clouds Newsletter, March 1998, Issue 18
http://singularity.astro.uiuc.edu/projects/mcnews/newsletter18.html
New Distance Determination to the LMC
Nino Panagia (1,2)
(1) Space Telescope Science Institute, 3700 San Martin Drive, Baltimore,
MD 21218, USA
(2) On assignment from the Space Science Department of ESA
Using the new reductions of the IUE light curves by Sonneborn et al.
(1997) and an extensive set of HST images of SN 1987A
we have repeated and improved Panagia et al.'s (1991) analysis to obtain
a better determination of the distance to the
supernova.
In this way we have derived an absolute size of the ring R_abs = (6.23
± 0.08) × 10^17 cm and an angular size R" = 808 ± 17
mas, which give a distance to the supernova d(SN1987A) = 51.4 ±
1.2 kpc and a distance modulus m-M(SN1987A) = 18.55 ±
0.05. Allowing for a displacement of SN 1987A position relative to
the LMC center, the distance to the barycenter of the Large
Magellanic Cloud is also estimated to be d(LMC)=52.0±1.3 kpc,
which corresponds to a distance modulus of m-M(LMC) =
18.58 ± 0.05.
Revising accordingly the zero point of the Cepheid distance scale, and
using the SNIa measured by Sandage and collaborators,
one finds a value of the Hubble constant H_0=60±6 km/s/Mpc.
Invited Talk at the Workshop ``Views on Distance Indicators", Sant'Agata
sui Due Golfi, Italy, 3-6 September, 1997, ed. F.
Caputo, Mem. S.A.It., in press.
For preprints, contact: panagia@stsci.edu