Astronomy

Quote:

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Originally Posted by Dreamwoven

In March-April 2016 Popular Astronomy(p.18) published an article on the search for extraterrestrial life. Quoting Sir Arthur C Clarke (https://en.wikipedia.org/wiki/Arthur_C._Clarke): "Two possibilities exist: either we are alone in the universe, or we are not. Both are equally terrifying".

Links to further reading:

The best link is, I think, the first one, as it poses some interesting dilemmas:
https://waitbutwhy.com/2014/05/fermi-paradox.html

The other two I include here pose the usual dilemmas:

https://www.space.com/25325-fermi-paradox.html
https://sv.wikipedia.org/wiki/Fermis_paradox

This website looks at the Search for ExtraTerrestrial Intelligence (SETI): https://seti.org

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Interesting LINK;
"There’s something called The Kardashev Scale, which helps us group intelligent civilizations into three broad categories by the amount of energy they use:

A Type I Civilization has the ability to use all of the energy on their planet. We’re not quite a Type I Civilization, but we’re close (Carl Sagan created a formula for this scale which puts us at a Type 0.7 Civilization).

A Type II Civilization can harness all of the energy of their host star. Our feeble Type I brains can hardly imagine how someone would do this, but we’ve tried our best, imagining things like a Dyson Sphere.
A Type III Civilization blows the other two away, accessing power comparable to that of the entire Milky Way galaxy.
...
That said, given that my normal outlook is that humanity is a lonely orphan on a tiny rock in the middle of a desolate universe, the humbling fact that we’re probably not as smart as we think we are, and the possibility that a lot of what we’re sure about might be wrong, sounds wonderful. It opens the door just a crack that maybe, just maybe, there might be more to the story than we realize."

https://waitbutwhy.com/2014/05/fermi-paradox.html

Quote:

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Originally Posted by Dreamwoven

There are some peculiar phenomena on our doorstep, one of which was identified by the Hubble Space Telescope:
https://www.universetoday.com/137278...asteroid-belt/.

This is a binary asteroid in the main asteroid belt between Mars and Jupiter.

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Some of it´s unusual features:
"Using the Hubble telescope, the team first observed 288P in September 2016, when it was making its closest approach to Earth. The images they took revealed that this object was not a single asteroid, but two asteroids of similar size and mass that orbit each other at a distance of about 100 km. Beyond that, the team also noted some ongoing activity in the binary system that was unexpected.

As Jessica Agarwal explained in a Hubble press statement, this makes 288P the first known binary asteroid that is also classified as a main-belt comet. “We detected strong indications of the sublimation of water ice due to the increased solar heating – similar to how the tail of a comet is created,” she said. In addition to being a pleasant surprise, these findings are also highly significant when it comes to the study of the Solar System."

Thanks, Danik, those were two interesting responses.

"Highest-energy cosmic rays have extragalactic origin

A 50-year-old debate has at last been settled: the highest-energy cosmic rays do not originate in our own galaxy but in galaxies located tens or even hundreds of millions of light-years away."

https://astronomynow.com/2017/09/26/...lactic-origin/

Your astronomy Now post is intriguing. But can we "read" what the high energy rays are communicating, if anything at all? I must subscribe to Astronomy Now! (Done).

Not yet, if they are comunicating anything at all. What also called my atention is that the observatory, in this case, is Argentinian.

"By comparing the arrival times of particles at the different detectors it is possible to determine where the cosmic ray particle that produced the air shower came from.

This discovery clearly indicates an extragalactic origin for these cosmic rays, since there is a probability of only one in five million that the pattern observed in the sky is due to chance. However, the study has not yet succeeded in locating the sources precisely. This is because the region where cosmic rays are brightest covers a large part of the sky, where the number of galaxies is relatively high. In addition, our galaxy’s magnetic field deflects the paths of these charged particles, making it more difficult to locate their sources."

The last issue of Popular Astronomy that I have (Jan-Feb 2017) has a lead article on Proxima b, asking if life could exist there. Proxima Centauri is the closest stellar neighbour to our Sun, and is a red dwarf star. Proxima b is an inner planet so may be made of rock and is in the so-called "habitable zone" of its star. we do not know whether Proxima b has water on its surface, nor if it has the ability to sustain an atmosphere. But the new Spitzer Space Telescope that came into service in 2016 - https://en.wikipedia.org/wiki/Spitzer_Space_Telescope - should be able to tell us more.

Two links about the Mars colonization project:

https://www.space.com/38315-spacex-m...fr-images.html

Elon Musk Wants Giant SpaceX Spaceship to Fly People to Mars by 2024

"SpaceX aims to launch its first cargo mission to Mars in 2022 and send people toward the Red Planet just two years after that."

https://www.space.com/38313-elon-mus...mars-2024.html

Deep Space Gateway: https://www.universetoday.com/137320...space-gateway/

There is a new enthusiasm for this internationally, led by the USA and Russia (NASA and Roscosmos jointly) and separately by China and India. The idea is to provide for a deep space gateway from which to explore the solar system.

I suppose it will have to be a joint venture between countries, because of the demanded technology and the expenses that arise from such a project and I think that is positive. Also there is the political aspect to consider.

I forgot to add Japan to the countries interested in the moon as a potential base. All have satellites going round the moon. Yes, the collaboration is necessary and, as you say, there is the political aspect to consider.

The country with the most advanced plans is clearly China. The new China mission - Chang'e3 - planned is is to have a rover/lander on board. Russia has invested most in the International Space Station and is picking sites for a moon base. So the political angle in the NASA-Roscosmos alliance is necessary if they want to be first to locate a site and begin the moon-base. This will in any case be permanently staffed by astronauts, once built. A new space-race is in then offing, though that is probably a few years away.

Yes. Once it startes it will be a race won by the powerfull countries with the most financial and technological resources. The age of the great discoveries will be reedited in its spacial version.

Meanwhile in Brazil:

"Cuts imperil Brazil’s stake in astronomy observatories
This is a very serious situation,” said Bruno Castilho, director of the National Astrophysics Laboratory in Itajubá, Brazil. His budget also was halved this year. Current reserves don’t even cover water and electricity bills, he says, let alone Brazil’s participation in the Gemini Observatory—twin optical and infrared telescopes in Chile and Hawaii—and the Southern Astrophysical Research Telescope in Chile. If Castilho can’t find at least another 4 million reais ($1.25 million) by the end of the year, he says, Brazilian astronomers will lose access to those facilities. The prognosis is grim, he says: “We don’t have anywhere else to cut.”

http://www.sciencemag.org/news/2017/...eril-brazil-s-
stake-astronomy-observatories

:bawling::bawling::bawling:

I forgot to add Japan to the countries interested in the moon as a potential base. All have satellites going round the moon. Yes, the collaboration is necessary and, as you say, there is the political aspect to consider.

The country with the most advanced plans is clearly China. The new China mission - Chang'e3 - planned is is to have a rover/lander on board. Russia has invested most in the International Space Station and is picking sites for a moon base. So the political angle in the NASA-Roscosmos alliance is necessary if they want to be first to locate a site and begin the moon-base. This will in any case be permanently staffed by astronauts, once built. A new space-race is in then offing, though that is probably a few years away.

I've been struggling to understand the dark energy debate. Gravitational waves (https://en.wikipedia.org/wiki/Gravitational_wave) and Black holes (https://en.wikipedia.org/wiki/Black_hole) are clearly connected. Black holes form as a result. As I see it, this means that black holes function as a sort of rubbish bin that can dispose of matter (like stars at the end of their lives when they become red dwarf stars?).

I'm not at home at this level of debate (though we all probably feel the same way) but perhaps we will learn more as time goes on.

See also https://astronomynow.com/2017/09/18/...energy-debate/.

See also https://www.universetoday.com/137319...les-colliding/