Astronomy

http://www.space.com/34629-nasa-fema...pact-test.html

It's a scary scenario: an asteroid headed for Earth, just four years away from slamming into our home planet. It may be too short a span to plan an asteroid-deflection mission, but it's long enough to present very different challenges from those of a more typical crisis, like a hurricane or earthquake.

"It's not a matter of if, but when, we will deal with such a situation," Thomas Zurbuchen, NASA's Science Mission Directorate's new associate administrator, said in a statement. "But unlike any other time in our history, we now have the ability to respond to an impact threat through continued observations, predictions, response planning and mitigation."

I wonder how different scales of threats can be taken into account. How about an exomoon propelled into a crash with the Earth? Or is this just about asteroids?

There is the movie "Melancholia" that dealt with the theme. In this case the planet Melancholia is much bigger than the earth and the earth will be the asteroid crashing into it. The assumption in the movie is that life existed no where else in the universe but on earth.

If the asteroid landed in deep water, the impact would probably be less than it if landed on land. However, if it landed on land this is one way that global warming might reverse since it should help cool off the climate. However, a good, hard global recession, even without an asteroid, would also stop global warming, at least, the part that we are causing.

There is a possibility that we are getting too close to the Venus zone and although still in the habitable zone where water is liquid, the atmosphere heats up too much. I suspect an array of satellites that reflected the sun's rays back out to space would help in this case.

I found this article on the astronomic basis of "Melancholia". It is an old comment though (2011):
http://blogs.discovermagazine.com/ba...0/meloncholia/

Outlier body incursions reminds me of the sci-fi movie classic "When Worlds Collide" https://en.wikipedia.org/wiki/When_W...de_(1951_film)

The SOCIETY for POPULAR ASTRONOMY
Electronic News Bulletin No. 433 2016 November 6
CURIOUS TILT OF SUN'S AXIS ATTRIBUTED TO PLANET 9

Europlanet Media Centre


'Planet Nine' -- the undiscovered planet that was predicted by astronomers in January this year to exist at the edge of the Solar System -- has been held responsible for the tilt of the Sun's axis,according to a new study. The large and distant planet may be adding a wobble to the Solar System, giving the appearance that the Sun is tilted slightly. The argument goes that, because Planet Nine is so massive and has an orbit tilted with respect to the orbits of the other planets, the Solar System is slowly twisted out of alignment. All of the known planets' orbits lie close to a particular plane, roughly within a couple of degrees of each other. That plane,however, has a six-degree tilt with respect to the Sun, giving the impression that the Sun's axis of rotation is at that angle from the normal to the planetary orbits. Until now, no one had found a good explanation for that. The discovery of evidence that the Sun is orbited by an as-yet-unseen planet that is about 10 times the size of the Earth, in an orbit that is about 20 times farther from the Sun on average than Neptune's, changes the physics. Planet Nine, according to the calculations, appears to orbit in a plane at about 30 degrees from that of the other planets, influencing the orbits of a large popula-tion of objects in the Kuiper Belt, which is how astronomers came to suspect that a planet existed there in the first place.


The tilt of the Solar System's orbital plane has long been a puzzle to astronomers because of the way the planets formed: as a spinning cloud slowly collapsing first into a disc and then into objects orbiting the central star. Planet Nine's angular momentum is having an outsizedimpact on the Solar System on account of its location and size. A planet's angular momentum equals the mass of the object multiplied by its distance from the Sun, and represents the contribution that the planet makes to the overall system's spin. Because the other planets in the Solar System all orbit in practically the same plane, their angular momenta work to keep the whole disc spinning smoothly. Planet Nine's unusual orbit, however, adds a wobble to the system.Mathematically, given the hypothesized size and distance of Planet Nine, a six-degree tilt fits perfectly. The next question, then, is how did Planet Nine achieve its unusual orbit? Though that remains to be determined, it is suggested that the planet may have been ejected from the neighbourhood of the gas giants by Jupiter, or perhaps may have been influenced by the gravitational pull of other stellar bodies in the Solar System's extreme past. For now, astronomers will be searching the sky for signs of Planet Nine along the path that they predicted in January. That search may take some time.

We still have no idea what Planet 9's orbit is, so it could take a long time to locate it and to have some idea of what its orbit can be.

If Planet 9 is not on the ecliptic it would not be where people are expecting it to be.

I don't think the planet in "Melancholia" is likely to exist, but the idea of looking to space for explanations for evolutionary changes on earth may be putting too much expectation on that source. The habitat/climate changes creating challenges for species and thereby allowing evolutionary changes to occur may have explanations that come from the earth itself, that is, volcanoes rather than meteorites.

http://www.universetoday.com/131818/...o-ula-atlas-v/

In a complete change of plans from less than three weeks ago, NASA has asked Orbital ATK to switch rockets and launch the firms next Cygnus commercial cargo freighter to the space station on the tried and true Atlas V rather than their own Antares rocket – which just successfully delivered another Cygnus to the orbiting outpost with a hefty stash of science and supplies.

The altered schedule “provides margin flexibility for the entire Antares workforce” Orbital ATK noted in a statement to Universe Today.

However, the change of events comes as something of a surprise following the spectacularly successful nighttime blastoff of Antares on Oct. 17 with the Cygnus OA-5 resupply ship from the Mid-Atlantic Regional Spaceport at NASA’s Wallops Flight Facility on Virginia’s picturesque Eastern shore – as I reported on from onsite.

I was attracted by the image:
http://www.astronomy.com/news/2016/1...axy-in-the-eye
"If it looks like spiral galaxy IC 2613 is staring at you, it’s not being rude: a collision with its nearest neighbor sent a wave crashing through the galaxy, which produced the strange eye-like structure."...

I wonder how much damage colliding galaxies would have on the life of a planet in one of those galaxies?

You would have to have read Worlds in Collision to begin to understand that. Velikovsky comments on p. 305 under "The subjective interpretation of events and their authenticity".

http://www.universetoday.com/30537/w...llanic-clouds/

WHAT ARE MAGELLANIC CLOUDS?

Article Updated: 8 Nov , 2016
by Matt Williams
Since ancient times, human beings have been staring at the night sky and been amazed by the celestial objects looking back at them. Whereas these objects were once thought to be divine in nature, and later mistaken for comets or other astrological phenomena, ongoing observation and improvements in instrumentation have led to these objects being identified for what they are.

For example, there are the Small and Large Magellanic Clouds, two large clouds of stars and gas that can be seen with the naked eye in the southern hemisphere. Located at a distance of 200,000 and 160,000 light years from the Milky Way Galaxy (respectively), the true nature of these objects has only been understand for about a century. And yet, these objects still have some mysteries that have yet to be solved.

The sheer size of phenomena and the huge distances involved are hard to grasp...

http://www.universetoday.com/131879/...-5-times-mass/

Red dwarf stars have proven to be a treasure trove for exoplanet hunters in recent years. In addition to multiple exoplanets candidates being detected around stars like TRAPPIST-1, Gliese 581, Gliese 667C, and Kepler 296, there was also the ESO’s recent discovery of a planet orbiting within the habitable zone of our Sun’s closest neighbor – Proxima Centauri.

And it seems the trend is likely to continue, with the latest discovery comes from a team of European scientists. Using data from the ESO’s High Accuracy Radial velocity Planet Searcher (HARPS) and HARPS-N instruments, they detected an exoplanet candidate orbiting around GJ 536 – an M-class red dwarf star located about 32.7 light years (10.03 parsecs) from Earth.

According to their study, “A super-Earth Orbiting the Nearby M-dwarf GJ 536“, this planet is a super-Earth – a class of exoplanet that has between more than one, but less than 15, times the mass of Earth. In this case, the planet boasts a minimum of 5.36 ± 0.69 Earth masses, has an orbital period of 8.7076 ± 0.0025 days, and orbits its sun at a distance of 0.06661 AU.

I would only add to this that (a) circumstellar habitable zone is far too broad a category to be of use in identifying planets that can be lived on by humans. Note that one restriction would be that the atmosphere is similar to that on Earth.

2.7 light years away is a major technological restriction to Faster the Light (FTS) travel. It means it would take that many years travelling at the speed of light to get there. There is as yet no technology to make travel at the speed of light possible. Even less possible is the idea of a warp drive, such as we know from Star Trek.

We may be at the start of the space age, but we aren't going to the stars, not by a long chalk.

I suspect every star has planets of some sort circling it. We just don't know about them. I agree that we are not going to send people to those planets, but we could communicate with them with a message delay of 2.7 years. I also suspect that life will form where ever it is possible for life to exist.

Quote:

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Originally Posted by YesNo

I suspect every star has planets of some sort circling it. We just don't know about them. I agree that we are not going to send people to those planets, but we could communicate with them with a message delay of 2.7 years. I also suspect that life will form where ever it is possible for life to exist.

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Assuming there are humans there that are about our level of technology. I doubt very much there are...

So far we haven't been able to find messages from anyone, but we have only started looking. We probably need to focus on those stars with exoplanets who could spot the Earth, if anyone there is looking, as one of their exoplanets. One of your previous posts mentioned doing something like this.