Ziegler–Castell–Grand Object

“Valentine’s day object” redirects here.

Formally designated 1I/2001 C1, it was initially discovered by Nicolas Ziegler and further observed by astronauts Christopher Castell and John Grand, during STS-98. It is the first astronomical object of interstellar origin to ever been discovered, and believed by many to be the first observed evidence of extraterrestrial intelligence.

Discovery

Ziegler’s first photograph of the object

Amateur astronomer and known comet hunter Nicolas Ziegler first discovered the object on February 3, 2001, in images he obtained using a Canon EOS D30 attached to a Cassegrain reflector. Initially thought to be a comet, Ziegler notified the Palomar Observatory upon confirming the object had not previously been identified.

High resolution images from the Samuel Oschin telescope revealed more details. Determining its orbit took three days, since the object’s angular movement relative to Earth was minimal.

Its hyperbolic, high velocity orbit was evidence of an object of extrasolar origin, and it was thus designated 1I/2001 C1. The second object to receive the Interstellar designation would be ‘Oumuamua, in 2017.

Observations

Although a tail was detected, it surprised scientists that it was not pointing away from the sun, but towards Earth.

Radar images did not show evidence of a rotating body, and telescope images revealed three bright lights at the center, surrounded by two concentric glowing rings. A blue light and a red light were sometimes seen rotating around the object every 39 and 14 hours, respectively.

Series of photographs depicting the object’s rotating light patterns

The object had a diameter of 23 km, far larger than expected for a comet.

Evacuation

As observations and calculation were refined, there was found to be very high probability of impact. Although its mass was never known with certainty, a collision with an object of that size would have long lasting global effects. Asuming a density of a stony asteroid and an impact velocity of 60 km/s, the object was estimated to release over 2,000,000 megatons of TNT.

On February 12, telescope images revealed a brightening of the object, turning it into a magnitude -4.0, visible in the night sky with the naked eye. A new orbit for the object was recalculated, as its velocity decreased from 60 km/s to 10 km/s in the span of a day.

NASA determined the object would pass 50 km above the Kármán line. STS-98 had completed its primary mission of installing the Destiny module on the International Space Station and the crew was expecting to undock four days later, but were notified by Mission Control Center to evacuate the station aboard Space Shuttle Atlantis, as there was a very high risk of collision.

Mission commander Kenneth D. Cockrell, after discussing with mission specialist Christopher Castell, refused the evacuation orders, as he noted that no telescope was positioned for observing the object during close approach. He informed Mission Control of their plans to observe the object as it made its close approach, to which Mission Control accepted after several rounds of discussion with scientists.

Observations further narrowed the object’s path, and no collision was expected to occur. Mission Control then gave permission to the crew to perform the spacewalk. The object was expected to pass between Earth and the International Space Station, providing an exceptional opportunity for close observation.

Flyby

Diagram of the object’s flyby on closest approach

On Valentine’s day, 2001, one hour before the object’s closest approach to the station, astronauts Christopher Castell and John Grand performed a spacewalk carrying photographic equipment and instruments to study the object.

Photograph taken by John Grand

Photographs taken before the closest approach revealed the object to be of a cylindrical shape, measuring approximately 68 km tall, its surface was described as rocky, almost metallic.

John Grand pointed the camera down as the object passed between the International Space Station and the Earth, revealing previously unknown features. The object’s top section seemed flat, with features that Castell described as “Continental landmasses and intricate rivers.”

Photograph by Christopher Castell as the object transited above the Argentinian Patagonia. The object appears blurred due to its high velocity relative to the station

Twelve hours after closest approach, the object once again increased in brightness and the tail was formed again. The object achieved a velocity of 142 km/s, in a hyperbolic trajectory away from the solar system. The crew of STS-98 safely returned to Earth at Edwards Air Force Base on February 20.

Hypotheses

Propulsion

Its rapid, controlled deceleration cannot be attributed to outgassing alone. An annihilation drive is considered to be the most likely source of propulsion for the object. Scientists believe the three center lights are the exhaust nozzles of the object. Spectrum analysis of the tail matches that of the emissions produced by hydrogen-antihydrogen annihilation. It is hypothesized that the object’s tail is the superheated propellant of the object’s propulsion system.

Organic Life

The photographs from Castell and Grand serve as the only observation records of the object’s top section. It is hypothesized some sort of biosphere is preserved by unknown methods.

Exploration

Telescopes are still pointing towards the object in search of any activity. The object keeps moving away from the solar system at a constant velocity. It can currently be found in the southern constellation Pavo.

Hypothetical space mission

Although the high hyperbolic excess velocity of 1I/2001 makes it hard for a spacecraft to reach it with existing technology, a mission to send an unmanned probe to 1I/2001 C1 has been proposed, conducting a flyby around Jupiter and the sun in order to take advanage of the Oberth effect, with an expected flight duration of 40 years.