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KF5JRV > TODAY 29.03.19 13:32l 27 Lines 1252 Bytes #999 (0) @ WW
BID : 33565_KF5JRV
Read: GUEST
Subj: Today in History - Mar 29
Path: IW8PGT<IZ3LSV<IK6ZDE<VE2PKT<N3HYM<KF5JRV
Sent: 190329/1131Z 33565@KF5JRV.#NWAR.AR.USA.NA BPQ6.0.18
The unmanned U.S. space probe Mariner 10, launched by NASA in November
1973, becomes the first spacecraft to visit the planet Mercury, sending
back close-up images of a celestial body usually obscured because of its
proximity to the sun.
Mariner 10 had visited the planet Venus eight weeks before but only for
the purpose of using Venus’ gravity to whip it toward the closest planet
to the sun. In three flybys of Mercury between 1974 and 1975, the NASA
spacecraft took detailed images of the planet and succeeded in mapping
about 35 percent of its heavily cratered, moonlike surface.
Mercury is the second smallest planet in the solar system and completes
its solar orbit in only 88 earth days. Data sent back by Mariner 10
discounted a previously held theory that the planet does not spin on its
axis; in fact, the planet has a very slow rotational period that
stretches over 58 earth days. Mercury is a waterless, airless world that
alternately bakes and freezes as it slowly rotates. Highly inhospitable,
Mercury’s surface temperature varies from 800 degrees Fahrenheit when
facing the sun to -279 degrees when facing away. The planet has no known
satellites.
73 de Scott KF5JRV
Pmail: KF5JRV@KF5JRV.#NWAR.AR.USA.NA
email: KF5JRV@ICLOUD.COM
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