By Alexandra Write
On a late July night during World War II, in the blackness of the Philippine Sea, a Japanese submarine happened to spot the cruiser USS Indianapolis backlit by the rising moon.
The submarine fired six torpedoes, two of which struck the Indianapolis. Within minutes, the ship was on its way to the bottom of the ocean, with 300 men dead and 900 more spewed into the shark-infested water.
No one came to their rescue. By five days later, when help finally arrived after an airplane spotted some men by chance, nearly 600 of the initial survivors had drowned, died of exposure, or been eaten by sharks.
Now scientists say the 1945 tragedy - the U.S. Navy’s worst disaster at sea - may have been caused in part by the moon being in the wrong place at the wrong time. Researcher Donald Olson has done some forensic astronomy on that moment, and his findings help clarify what happened that night.
The Japanese submarine, the Indianapolis and the moon, he says, were roughly lined up at the moment of sighting.
“Once this alignment happened, the ship was basically doomed,” says Dr. Olson, a professor at Southwest Texas State University in San Marcos.
“I don’t know if I should use the word unlucky, because that seems to trivialize it,” he adds. “This was an accident of war, or maybe of fate.”
Visibility that night was best toward the east, he says - the exact direction in which the submarine commander happened to be looking.
Capt. William Toti, a naval expert on the case of the Indianapolis, calls Dr. Olson’s study “the definitive work explaining the astronomical nuances that went into ... [the submarine commander’s] ability to sight and sink the Indianapolis.”
The study, written with professor Russell Doescher and student Brandon Johns, appears in the July issue of Sky & Telescope magazine.
The Southwest Texas State team specializes in tracking down the astronomical circumstances surrounding historical events. In 1987, for instance, it explained the peculiar tides during the 1943 landing at Tarawa Atoll, in which landing boats grounded on coral reefs, forcing Marines to wade ashore into machine-gun fire. Dr. Olson became interested in the Indianapolis after reading a magazine article about a young Florida student’s attempt to clear the captain’s name.
After the Indianapolis was sunk, its captain, Charles McVay, was court-martialed and convicted of negligence. (Capt. McVay killed himself in 1968. He was exonerated by Congress in 2000 and by the Navy last year, after much lobbying by the student and surviving crew members.) Much of the court-martial focused on the fact that Capt. McVay had not steered the cruiser, which had no protective escort, in a zigzag pattern to throw off enemies. But zigzagging would have made no difference, Dr. Olson’s new study confirms.
On the fatal night of July 29-30, 1945, the Indianapolis had been traveling to the Philippines from the island of Tinian, where it had dropped off the uranium core and other components for the atomic bomb that eventually devastated Hiroshima. Survivor and other historical accounts describe the night as overcast, with the clouds occasionally parting to reveal the moon.
But the moon that night wasn’t a “half-moon” as often described, Dr. Olson says. Instead, its face was three-quarters illuminated, providing plenty of light. At the time of sighting, the moon would have been about 15 degrees - the equivalent of a fist and a half’s width held at arm’s length - above the horizon, having risen an hour before.
The Japanese I-58 submarine, under the command of Mochitsura Hashimoto, spotted the Indianapolis during a routine periscope check at 11:35 p.m. cruiser time. (The Indianapolis was operating on a time zone 30 minutes ahead of the submarine.)
Historical sources generally hold that the submarine and cruiser lay six miles apart at sighting, while the Japanese estimated the distance as closer to seven and a half miles. Based on the visibility that night, Dr. Olson thinks the two vessels were even farther apart - something like 10 miles.
Visibility was greatest, by far, in the eastward direction where the Indianapolis happened to lie. Had the cruiser been to the north, west or south of the submarine, it might have remained undetected, he says.
“There’s a big difference between an ordinary moonlit night and what happened to the Indy,” says Dr. Olson. Capt. Toti, former commander of a submarine named in honor of the Indianapolis, agrees.
“My experience is that you can see a lot farther when looking into the moonlight than you can when looking away from it,” he says. “Dr. Olson’s research explains why the submarine was able to clearly see the Indy at the same time that crew members on the Indy described the visibility as poor.”
Some survivors described near-blackness as they tried to abandon ship; others describe clouds occasionally breaking and clearing the face of the moon.
“The night this happened, I can guarantee you there was a moon, but there was also an overcast,” says survivor Glenn Morgan. “The moon was bright enough to put a kind of faint glare on the water. ... I never remember it being totally blacked out.”
Mr. Morgan, who lives in Robertson County in Central Texas, served as buglemaster aboard the Indianapolis. He survived by clambering into a life raft with about 20 other men, one of whom died during the five-day ordeal. Until the group was rescued, the men had no idea there were any other survivors. (Of the 316 original survivors, 108 are still living.)
SOS messages were sent from the sinking Indianapolis, but various factors - including a naval directive that did not require the nonarrival of fighting ships to be reported - kept the message of the disaster from making it up the Navy’s chain of command. A fleet of ships and airplanes eventually rescued the fragmented, floating groups of men.
The shipwreck has never been found, and many people know the story only through its brief mention in the movie Jaws.
This July 29, as happens every 19 years, the spot where the cruiser sank will experience a near-repeat of the lunar conditions of July 29-30, 1945. A celestial coincidence will cause the moon to rise at the same time, and in the same phase, as the night of the sinking, says Dr. Olson.
Were an observer to float on the moonlit sea, several miles above the Indianapolis’ wreckage, he might gain a better appreciation for exactly how the cruiser was doomed, Dr. Olson says.
“This one is poignant.”