From Mitsuru SOMA
●･･････Date: Wed, 2 July 2003 23:57:20 +0900 (JST)
From:
Mitsuru SOMA <somamt@ybb.ne.jp>
Reply-To:
somamt@cc.nao.ac.jp
To:
VZV03210@nifty.ne.jp
Subject:
Fwd: Re: Mars closest approaches
Masatsugu MINAMI さま
国立天文台の相馬と申します．今回に匹敵する前回の火星接近はいつかについて，混乱がありましたので，Jeffrey
Beish に尋ねたところ，MINAMIさんに聞けば詳しいことがわかるだろうと言って来ました．Beish
からの返事をコピーしておきます．この件に関して何かご存じでしたらご教示いただきたく，よろしくお願いいたします．
国立天文台 位置天文・天体力学研究系
相馬 充
--- DustyMars <dustymars@tnni.net> からのメッセージ：------------------------------------------------------
>
From: "DustyMars"
<dustymars@tnni.net>
>
To: "Mitsuru SOMA" <somamt@cc.nao.ac.jp>
>
Subject: Re: Mars closest approaches
>
Date:
>
> I must have misunderstood your question and copied my
reply in error. The
> correct answer is 57,538 BC or -57,537. Actually, the article states that
> we used my birthday,
> compute simulation. No good reason for that particular
date. We state that
> Mars was the same closeness 57,237 + 2001 years ago or
almost 60,000 years
> ago. I
think if you contact Masatsugu MINAMI at VZV03210@nifty.ne.jp he may
> explain what I try to say much better than I can.
>
> My reply to you must have been lost. Sorry.
>
> Thanks,
>
> Jeff Beish
>
> ----- Original Message -----
> From: "Mitsuru SOMA"
<somamt@cc.nao.ac.jp>
> To: <dustymars@tnni.net>
> Sent:
> Subject: Re: Mars closest approaches
>
>
> > Dear Dr. Jeffrey D. Beish,
> > On May 21, you replied
to my question as follows:
> > >Thank you for the interest in my results. Attached is a zipped file
> > >of the article: Beish, J.D., "The
Opposition Cycle of Mars," Journal
> > >of the Association of Lunar and Planetary
Observers (J.A.L.P.O.),
> > >Vol. 44, No. 4, autumn 2002, pp. 44-45. I hope this helps.
> > >To answer your question it is -55536 = 55537
B.C.
> >
> > Today I found the following article:
> > http://skyandtelescope.com/observing/objects/planets/article_970_1.asp
> > It says "According to a calculation by the
Association of Lunar
> > and Planetary Observers' Jeffrey Beish and James DeYoung, Mars
> > came a little closer to Earth in 57,537
BC." This contradicts
> > your reply to my question copied above. Could you explain again
> > which is your correct result? Please also note that I sent the
> > message copied below to which I do not think I
have received your
> > reply yet.
> >
> > Best regards, Mitsuru Soma
> >
> >
> > -----
> > Date:
> > From: Mitsuru SOMA <somamt@cc.nao.ac.jp>
> > To: dustymars@tnni.net
> > Subject: Re: Mars closest approaches
> >
> > Dear Dr. Jeffrey D. Beish,
> > On May 21 you
kindly sent me the article:
> > Beish, J.D., "The Opposition Cycle of Mars," Journal of the
>
> Association of Lunar and Planetary Observers (J.A.L.P.O.),
>
> Vol. 44, No. 4, autumn 2002, pp. 44-45,
> > with the figure of the Mars diameter at the
closest approach
> > for a period of +/-100,000 years from the year
2001.
> > You also wrote to me:
> > >To answer your question it is -55536 = 55537
B.C.
> > which means that the last time Mars was closer to
Earth
> > than this year's was in 55537 B.C. (The year was
written
> > in your article as -57,537 and your answer
indicated that
> > it was counted from the year 2001). However, when I looked
> > at your figure of Mars diameter, I found that this
number
> > (55537 B.C.) seemed to be inconsistent with the
figure.
> > We can obtain the Julian Date for the year 55537
B.C.
> > as approximately -1.86 x 10^7, but from the figure
> > I estimated that the Julian Date of the last time
> > the Mars diameter was greater than 25.11 arcsec (this year's
> > greatest Mars diameter) was approximately -1.93 x
10^7,
> > which is different from the above JD value -1.86 x
10^7 by
> > about 2000 years. In your article you also gave two years
> > -79,241 and +25,695 as the years of the highest
points in
> > the figure, and these seem to have the same
inconsistency.
> > So I would like to ask if you could provide the
Julian Date
> > of the last time Mars was closer than this year's.
> > I would also like to ask you to clarify which
number of the
> > days in the year you used to obtain the year
-57,537,
> > the Julian year (365.25) or the Gregorian year
(365.2425)
> > or the solar year (365.2422), because the
difference between
> > 365.25 and 365.2425 (or 365.2422) makes the
difference of
> > more than one year when one converts the JD of
about
> > -1.9 X 10^7 to the year.
> >
> > Thanking you in advance and with best regards,
> >
> > Mitsuru Soma
> > National Astronomical Observatory
> > Osawa 2, Mitaka,
> >
> >
○･･････Date:
Fri, 4 July 2003 21:30:58 +0900
(JST)
From:
Mitsuru SOMA <somamt@cc.nao.ac.jp>
Subject:
RE:Fwd: Re: Mars closest approaches
南 政次 様
国立天文台の相馬です．
お忙しいところ，早速お返事をいただきまして誠にありがとうございます．MINAMIさんというのは『天文年鑑』などに執筆されている南さんだったのですね．失礼しました．
ご紹介いただきましたウェブは存じておりました．実を言えば，今回の事はそのサイトに書かれていたことが発端だったのです．渡部潤一さんから前回の接近について聞かれたときに，そのサイトに書いてあったことを教えてあげたのですが，渡部さんはそこに紹介されていた
Beish さんの論文にあった the year -57537 を紀元前57537年と解釈してニュースを流してしまったのです．わたしはそのサイトに「57537年前」とあったことと，論文には2001年の
Beish さんの誕生日を基点として計算したとあったことから，-57537 というのは2001年から数えたものかも知れないと思い，それを明らかにしてくれるように
Beish さんにメールで頼んだのです．その返事が「紀元前55537年」だったのです．先のニュースはこれに基づき訂正されました．しかし，これは Sky
& Telescope ６月号に紹介されていたイタリアのAldo Vitagliano さんの「紀元前57617年」とは約2000年の差があったため，外部から，どうしてそんなに差があるのかという質問が来たのです．それで今回の問い合わせとなった次第です．今回，南さんからお送りいただきましたメールには
Standish さんのことも書かれていましたが，その点に関しても何か誤解があるように感じます．といいますのも，私は
Standish さんにも今回の件を尋ねたのですが，彼は自分では計算しておらず，Vitagliano さんの結果を支持しておられたからです．参考として，Beish
さんとの最初のメールと Standish さんからの返事を下に示しておきます．
約６万年前という結果の信頼性について，Vitagliano さんは，小惑星を入れるか入れないか（それは内惑星の運動にかなり影響するはず）で比較し，さらに，最新の暦
DE406 と比べて精度がかなり劣るはずのDE200 を初期値として同じ計算を試みて，紀元前57617年の接近の日時の差が１時間以内，接近距離の差も5000km以内ということだったということで，暦の誤差を考慮しても信頼できる結果であると述べています．Standish
さんも彼の計算をかなり信頼していますので，私もこの結果は信頼できるものだろうと考えています．全く異なる
Beish さんの計算でも結局，日時の差は大接近の起こる間隔の79年ということで，これもかなり良く一致していると思います．
それでは，今後ともよろしくお願い致します．
相馬 充
-----------------------------------------------------------------
Date:
From: Mitsuru SOMA <somamt@cc.nao.ac.jp>
To: dustymars@tnni.net
Subject: Mars closest approaches
Dear Dr. Jeffrey D. Beish,
From the web site of the Japanese OAA Mars Section:
http://www.kwasan.kyoto-u.ac.jp/~cmo/cmooaa_mars.html
I learned that you had a talk in
the closest approaches of Mars during a period of
+/-100,000 years from the year 2001. I am very interested
in the results.
It says that the preceding closest
approach similar to this year occurred in the year -57537.
I would like to clarify how the year is counted. Is this
"year -57537" counted in the manner of
astronomical chronology
(i.e. -57537 = 57538 B.C.)? Or is it from the year 2001
(i.e. "the year -57537" = 2001-57537 = -55536 =
55537 B.C.)?
Thank you in advance and sincerely yours,
Mitsuru Soma
National Astronomical Observatory of
Mitaka,
-----------------------------------------------------------------
From: "MustyMars"
<dustymars@tnni.net>
To: "Mitsuru SOMA" <somamt@cc.nao.ac.jp>
Subject: Re: Mars closest approaches
Date:
Dear Mitsuru Soma,
Thank you for the interest in my results. Attached is a zipped file of the
article: Beish, J.D., "The Opposition Cycle of Mars,"
Journal of the
Association of Lunar and Planetary Observers (J.A.L.P.O.),
Vol. 44, No. 4,
autumn 2002, pp. 44-45.
I hope this helps. To
answer your question it
is -55536 = 55537 B.C.
Thanks,
Jeff Beish
-----------------------------------------------------------------
Date:
Thu,
From:
Myles Standish <ems@smyles.jpl.nasa.gov>
To:
somamt@cc.nao.ac.jp
Subject:
closest approach of Mars
Hi, Mitsuru
It is nice to hear from you; I trust things are going well.
For the Mars close approach, the following address is of
interest:
(all one address).
It says
"According
to Italian mathematician Aldo Vitagliano of
the
mythological Roman god of war, will come closer to the Earth this summer than
it has in more than 50,000
years. How this
amazing figure was arrived at is an interesting story. Belgian author and
mathematician Jean Meeus described
how the
distance between the orbits of Mars and Earth varied in the distant past (1). Meeus calculated that Mars has not
been closer to
Earth since the year 73,000 B.C. His findings were published in news media all
over the world. However,
Meeus now says his initial calculations,
which were based on the work of French astronomer Pierre Bretagnon,
are off by
more than
20,000 years. After his book was published, Meeus
contacted Vitagliano and asked him to investigate the
motion
of Mars by
numerical integration. In April 2002, Vitagliano told
Meeus the last time Mars was closer to Earth than
this
year's
spectacular opposition was on September 12 of the year 57,617 B.C."
...
I had a long correspondence with Vitagliano
when he was writing his
program. He
seemed to be very capable, and he was quite careful about
his program.
Therefore, I would tend to trust his results.
His paper may be found on the following website:
http://main.chemistry.unina.it/~alvitagl/solex/MarsDist.html
This gives an idea of his accuracy.
As for the discrepancy in dates, I don't know why they
occur. I do not know of De Young.
I hope this helps.
Best regards,
Myles
相 馬 充 (Mitsuru Soma, 国立天文台, Tokyo)
somamt@ybb.ne.jp