Space News: Rogue star hit solar system, life on the Moon?

[Brian G Turner]

A couple of juicy space stories in the news this week:

1. Rogue star hit solar system?

Research suggests a rogue star might have skimmed the early solar system: Did a rogue star change the makeup of our solar system?

In recent years, space scientists have begun to suspect that something out of the ordinary happened to our solar system during its early years. Many have begun to wonder why there is not as much material in the outer solar system as logic would suggest. Also, why is Neptune so much more massive than Uranus, which is closer to the sun? And why do so many of the smaller objects in the outer solar system have such oddly shaped orbits? In addressing such questions, many space scientists have begun to wonder if a star might have wandered by during the early years of the solar system—coming just close enough to pull some of the objects in the outer parts of the solar system from their prior positions.

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To test their theory, they created a simulation of just such a scenario and found that it very closely matched what we are able to see today—a solar system with odd characteristics at its outer edges.

2. Andromeda ate sibling?

The Milky Way and Andromeda are the 2 largest in our Local Group of galaxies - but simulations suggest the 3rd largest may have been ripped apart and absorbed by Andromeda, 2 billion years ago: The Milky Way's long-lost sibling finally found

This galaxy, called M32p, which was shredded by the Andromeda galaxy, was at least 20 times larger than any galaxy which merged with the Milky Way over the course of its lifetime. M32p would have been massive, making it the third largest galaxy in the Local Group after the Andromeda and the Milky Way galaxies.

This work might also solve a long-standing mystery: the formation of Andromeda's enigmatic M32 satellite galaxy, the scientists say. They suggest that the compact and dense M32 is the surviving center of the Milky Way's long-lost sibling, like the indestructible pit of a plum.

"M32 is a weirdo," Bell said. "While it looks like a compact example of an old, elliptical galaxy, it actually has lots of young stars. It's one of the most compact galaxies in the universe. There isn't another galaxy like it."

3. Did the moon once have life?

Early during its formation, our Moon could have been a warm and wet place - conducive to life: Researcher sees possibility of Moon life

Schulze-Makuch and Ian Crawford, a professor of planetary science and astrobiology at the University of London, say conditions on the lunar surface were sufficient to support simple lifeforms shortly after the Moon formed from a debris disk 4 billion years ago and again during a peak in lunar volcanic activity around 3.5 billion years ago.

During both periods, planetary scientists think the Moon was spewing out large quantities of superheated volatile gases, including water vapor, from its interior.

Schulze-Makuch and Crawford write that this outgassing could have formed pools of liquid water on the lunar surface and an atmosphere dense enough to keep it there for millions of years.

"If liquid water and a significant atmosphere were present on the early Moon for long periods of time, we think the lunar surface would have been at least transiently habitable," Schulze-Makuch said.

4. All known near asteroids - visualized

NASA has released a video animation showing all known asteroids near to Earth's orbit - and that space is busier than it looks:

5. Hire a meteor shower

A Japanese start-up claims it will be able to offer meteor showers by demand, from 2020.

By launching a satellite filled with tiny balls, they claim they could aim these at specific areas of Earth's atmosphere at specific times - providing a display to outshine any fireworks display: : Shooting stars on demand: Japan start-up plans 2020 meteor shower


Bonus! Headless snake challenged dinosaurs

A team scanning amber realized one of the creatures trapped in there was actually a snake. Although missing its head, it becomes only the 15th fossilized snake found to date: First snake found in amber is a baby from the age of the dinosaurs

First snake found in amber is a baby from the age of the dinosaurs

 

[REBerg]

NASA has released a video animation showing all known asteroids near to Earth's orbit - and that space is busier than it looks:

The visualization is as frightening as it is beautiful.
I had thought that the possibility of asteroids hitting the earth was negligible. Now, I wonder how they can miss.

 

[Brian G Turner]

Research suggests a rogue star might have skimmed the early solar system: Did a rogue star change the makeup of our solar system?

There's a small update on this, namely as the study has now been published: Impact of a stellar intruder on our solar system

However, the most surprising finding was that a fly-by does not only explain the strange orbits of the objects of the outer solar system, but also gives a natural explanation for several other unexplained features of the solar system, including the mass ratio between Neptune and Uranus, and the existence of two distinct populations of Kuiper Belt objects.
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This is no final proof that a stellar fly-by caused the messy features of the outer solar system, but it can reproduce many observations and seems relatively realistic. So far, it is the simplest explanation, and if simplicity is a marker of validity, this model is the best candidates so far.

 

[Lumens]

The visualization is as frightening as it is beautiful.
I had thought that the possibility of asteroids hitting the earth was negligible. Now, I wonder how they can miss.

In order to get an idea of the sheer enormity of the solar system, visiting a scale model of it can be useful. Hopefully it should put your mind at rest as well.

Solar System model - Wikipedia

 

[Brian G Turner]

2. Andromeda ate sibling?

There's more about this today at Phil Plait's blog, not least more on the circumstantial evidence to support the claim: Two billion years ago, Andromeda ate the Milky Way’s sibling