A visualization by LeoLabs of the possible collision of two defunct spacecraft in January 2020.

Two old, out-of-control spacecraft are currently on a possible collision course above Pittsburgh on Wednesday night, hurtling toward each other in orbit.

The objects are set to cross paths at 6:39 p.m. EST and will come within at least 40 feet of each other, according to space radar company LeoLabs. That puts the probability of a collision at 1 in 100, the company says, which is an exceptionally high likelihood.

"The way the industry works today, one in 10,000 is considered noteworthy, one in 1,000 is considered an emergency event and one in 100 is extremely concerning," LeoLabs CEO Dan Ceperley told CNBC.

A U.S. Department of Commerce spokesperson told CNBC that its Office of Space Commerce is tracking the close approach, noting that the increasing number of objects and debris in space is making near-miss events like this unfortunately more common. The Commerce Department is in the process of assuming responsibility from the Pentagon to track objects and notify companies about potential collisions.

One of the spacecraft is a large decommissioned telescope, launched in 1983, and the other is an experimental U.S. spacecraft launched in 1967. The latter object has an 60-foot-long boom sticking out from it, LeoLabs noted, which means the probability of a collision is as low as 1 in 20 when accounting for the size of the object.

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If the defunct spacecraft collide, Ceperley says the extreme velocity of the objects would add a deadly new cloud of debris in space. LeoLabs data shows the spacecraft moving at a relative velocity of nearly 33,000 miles per hour – or 43 times the speed of sound.

"If these things collide, that's thousands of new pieces of debris and they're going to be up there for centuries. So all of a sudden there is a huge new risk and we've got no way to deal with it," Ceperley said.

He added that LeoLabs should know within a few hours of the event whether they collided, as Ceperley said his company will be able to "see if there's one satellite or a whole bunch of bits, a cloud of debris."

To be sure, a collision would not pose any threat to Pittsburgh, or likely any other place on Earth. The pass will occur at an altitude of 559 miles above the Earth and any debris that falls through the atmosphere should largely burn up during reentry.

Ceperley does not think the collision will be visible by people without the aid of a large lens.

"This is the sort of thing that with some telescopes you could track, but not with the naked eye," Ceperley said.

Dan Oltrogge, director of AGI's Center for Space Standards and Innovation, told CNBC that "it's possible you could see something" of the collision but that "the most dramatic of this would be reentry of fragments later in the orbit." AGI (Analytical Graphics, Inc) is a company that makes software built to analyze important assets in space.

AGI estimates that there may be as many as 200,000 objects whizzing around in orbit around the Earth. This includes objects as small as two centimeters – which, moving at thousands of miles per hour, are deadly to anything they hit. Additionally, Oltrogge noted that near-miss events are increasing in regularity as space becomes more crowded.

"Very close events like this for objects we track are on the order of every month or two months," Oltrogge said.

If these two spacecraft collide, Oltrogge estimated that it may create a cloud of debris with as many as 15,000 pieces that are at least one centimeter in size.