The new study is titled “Evidence that 1I/2017 U1 (‘Oumuamua) was composed of molecular hydrogen ice.” The authors are Darryl Seligman (Dep’t. of Geosciences, University of Chicago) and Gregory Laughton (Dep’t. of Astronomy, Yale University.) The paper has been accepted for publication in The Astrophysical Journal Letters.

“It’s a frozen iceberg of molecular hydrogen,” said Seligman in a press release.

And if it’s true, it’s likely that the galaxy is full of similar objects.”.

At the time, Seligman told NBC News, “We are quite confident in our hypothesis, and do not believe that there is a need to rely on alternative, less likely explanations for the non-gravitational acceleration.” At the same time, co-author Batygin told NBC News, “What our paper demonstrates is that some of its remarkable properties can be understood within the framework of relatively standard cometary physics.”.

In thier new paper, Seligman and Laughton have refined that idea, writing “We show that all of ‘Oumaumua’s observed properties can be explained if it contained a significant fraction of molecular hydrogen (H2) ice.”.

In a press release, Seligman added that “The only kind of ice that really explains the acceleration is molecular hydrogen.”.

The sublimation of the molecular hydrogen ice explains `Oumuamua’s acceleration.

In their paper, Seligman and Laughton explain that “H2 sublimation at a rate proportional to the incident solar flux generates a surface-covering jet that reproduces the observed acceleration.”?

The authors say that the molecular hydrogen ice also explains `Oumuamua’s strange cigar shape, unusual for an object in space?

In a press release, Seligman explained it in plain language: “Imagine what happens to a bar of soap.

Quite likely, the researchers say.

“…it’s likely that the galaxy is full of similar objects.”.

“That we saw one at all implies that there’s a ton of these things out there,” Seligman said.

There aren’t many possibilities, according to Seligman and Laughton.

They say that `Oumuamua likely formed in a Giant Molecular Cloud (GMC), the same structure that stars form from.

That means that `Oumuamua, and other objects like it, should hold clues to what’s going on inside GMCs.

If there was some way to intercept one of these objects, we could learn a lot.

It’s like the galaxy made it, and FedExed it out straight to us,” said Seligman.

If Seligman and Laughton are correct, then we should keep our telescopic eyes open for the next `Oumuamua that comes through our system.

Though `Oumuamua was the first one of these hydrogen icebergs we’ve spotted, that fact alone doesn’t tell us much about their abundance.

The authors think there’s likely a great number of these objects, and that their numbers has consequences for planet formation.

“If ‘Oumuamua’s anomalous acceleration stemmed from sublimating H2 ice, it is likely that a large population of similar objects exists,” they write in their paper

(2018) suggests that the space density of ‘Oumuamua-like objects is n = 0.2 AU-3

A galactic sea of unbound planetesimal-sized objects has potential consequences for star and planet formation.”