Death of a Neutron Star - Eric Kotani [9]
"I understand that a neutron star's mass is not so different from that of an ordinary star," Ensign Kim said. "But practically every book and article I've read about neutron stars mentions the destructiveness of the tidal force in its vicinity. Why?"
Janeway almost wanted to laugh as Maalot beamed the smile of a happy professor fielding questions from a bright student. "An excellent question! The strength of a gravitational field is in proportion to the total mass of the gravitating body, but it is also inversely-note 'inversely'- proportional to the square of the distance from it."
Paris's eyes widened in confusion and anxiety.
B'Elanna smiled and patted his hand, but Tom ignored her.
Dr. Maalot kept smiling, but nodded. "I'm sorry. Let me put it this way. A neutron star is typically only about ten kilometres in radius-in contrast to the radius of a main sequence G-type star, whose radius is measured upward of a million kilometres. Thus, an object can get quite close to that great mass of a neutron star. Closer than a ship could ever go to a normal star."
"Which then makes the gravitational force a ship experiences even more tremendous," Janeway said.
"Exactly," Maalot said. "What's more, the tidal force increases in inverse proportion to the cube of the distance from the center of the mass. Thus, any ordinary matter approaching a neutron star too closely would be ripped apart by the inexorable tidal force in its proximity."
"Almost before it knew what hit it," B'Elanna said.
Tom looked even more puzzled. "Put it this way," Janeway said. "Even if a ship were made of a mythical, indestructible unobtanium, it and everything and everyone inside the ship would be torn apart at a molecular level if the ship went too close."
Even Kim was starting to look perplexed now. "Ensign, you're not following this?" Janeway asked.
"No, I understand," Kim said, "but how can you have a binary neutron star system? It seems to me that one companion, or the other-possibly both-would be torn apart by the tidal force of the companion."
"Another good question," Dr. Maalot said, again smiling. "Theory is that neutron stars are so tightly bound by their own formidable gravitational field that they can orbit around each other forming a binary pair without being torn up by the other."
"Their intense gravity serves to hold them together," Janeway said.
"Exactly," Dr. Maalot said.
Kim nodded.
"But only up to a certain point of proximity," Dr. Maalot said. "When the two stars are nearly in contact with each other, all hell can, and does, break loose."
"Like any two colliding stars," Paris said.
"No," Dr. Maalot said. "Much worse."
"Not even on the same scale," B'Elanna said.
Janeway nodded. "You have to understand how a neutron star is formed. They are the final stage in the evolution of massive stars, usually formed in the collapsing core of a super giant after the star has exhausted its fuel. The colossal amount of energy released in such a core collapse propels the enveloping atmosphere explosively away."
"So, basically, this is a supernova," Chakotay said.
Janeway nodded.
"And that leaves a neutron star in its place?" Tom asked.
"Exactly," Janeway said.
"Got it," Paris said.
Janeway glanced around. Kim nodded. Dr. Maalot gestured for her to continue. "A neutron star might also be formed, if a white dwarf star becomes too massive by accreting matter from a companion, and exceeds the upper mass limit for a white dwarf. It would then collapse under its own weight and become a neutron star."
"Was that how this binary was formed?" Paris asked.
The doctor shrugged. "We can't say for sure how this particular pair came into being. In fact, we have little idea how such a pair would ever form."
Janeway nodded. "One of the rarest things in all the universe."
"So," Kim said, "why is, as you put it, all hell going to break loose?"
Dr. Maalot actually laughed.