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Post by jandl100 on Jul 18, 2020 8:42:16 GMT
It's 5 years since NASA's New Horizons spacecraft flew past the minor planet Pluto. After a voyage of nearly 10 years and more than 3 billion miles, the piano-sized probe flew within 7,800 miles of Pluto. For the first time ever, we saw the surface of this distant world in spectacular, colored detail. A lot of analysis of the data received from that encounter has been done. It turns out that Pluto is a fascinating world in its own right and is unique in our solar system in many ways. Here's an article providing an easy read about what's been discovered so far ... phys.org/news/2020-07-cool-pluto-horizons.html
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Post by MartinT on Jul 18, 2020 10:45:37 GMT
I was surprised that Apollo 15 'Falcon' had such an angle on it considering how slowly they took the descent.
Bad news on the James Webb.
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Post by TheMooN on Jul 20, 2020 15:34:13 GMT
NASA image of Colombia breaking Earth orbit.
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Post by jandl100 on Aug 2, 2020 11:35:55 GMT
Gliese 3470c - the first exoplanet discovered by amateur astronomers. And using a 12.5 inch telescope in a guy's back yard! The possible planet (it needs to be confirmed by further observations) is likely 10x the diameter of Earh (Saturn-sized) and with a 'year' of 66 days. The parent star is half the size of our Sun so a lot less bright, in fact the new planet lies in the 'habitable zone' where liquid water could exist on its surface. A Neptune-sized planet had already been discovered around the star (Gliese 3470b). And the observations made include hints of other planets existing in the system. www.sci-news.com/astronomy/saturn-like-exoplanet-habitable-zone-gliese-3470-08658.html
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Post by jandl100 on Aug 4, 2020 8:16:59 GMT
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Post by MartinT on Aug 4, 2020 8:34:00 GMT
How long do they take to arrive?
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Post by jandl100 on Aug 6, 2020 11:25:01 GMT
Interesting article about the atmosphere of the planet Venus. www.sciencealert.com/an-epic-planet-scale-wave-has-been-hiding-in-the-toxic-clouds-of-venus-for-decades"... Venus is an extreme sort of place for a rocky habitable zone planet. It's completely shrouded in a thick atmosphere made up almost entirely of carbon dioxide that rotates 60 times faster than the planet itself, producing insane winds. The atmosphere rains sulfuric acid, and its atmospheric pressure at 0 altitude is almost 100 times greater than Earth's. If that weren't bad enough, it's lander-meltingly hot, with an average surface temperature of 471 degrees Celsius (880 degrees Fahrenheit). That cloudy atmosphere is a fascinating place, and prone to huge waves. A bow-like structure 10,000 kilometres long that comes and goes in the upper atmosphere is a stationary gravity wave, thought to be generated by the rotating atmosphere blowing up against a mountain on the surface..."
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Post by jandl100 on Aug 6, 2020 11:46:53 GMT
.... which led me on to investigate the Soviet Venera space probe programme to Venus. A lot more in it than I knew about, which was vague memories of fairly poor photos from a lander. Quite an interesting article - www.fromspacewithlove.com/venera/
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Post by MartinT on Aug 6, 2020 12:07:07 GMT
The atmosphere rains sulfuric acid, and its atmospheric pressure at 0 altitude is almost 100 times greater than Earth's. If that weren't bad enough, it's lander-meltingly hot, with an average surface temperature of 471 degrees Celsius (880 degrees Fahrenheit). Yet still a more appealing holiday destination than Bournemouth.
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Post by jandl100 on Aug 7, 2020 16:02:54 GMT
Thousands or millions of planets might be orbiting our Milky Way galaxy's central super massive black hole (SMBH). They will probably be called blanets to distinguish them from the usual type of planets that orbit around stars. Although they may well be very similar, just a lot more lonely. Planets around stars seem to form from the disk of debris left after a star forms from its parent cloud of gas and dust. A similar, but hugely vaster, disk of debris exists around SMBHs, so it seems reasonable that blanets will form there in a similar way. The "sticking point" (pardon the pun, which will shortly become evident) is ice - that seems to be needed to form planets as ice covered granules are much more likely to stick together than bare pebbles, which would tend to just bounce off each other. Around a really big SMBH ice is unlikely to form as those black holes kick out a viscious amount of energy making things literally too hot for ice. But around a smaller SMBH (like the one at the centre of the Milky Way - a mere 4 million solar masses, compared to the more usual type that are in the billions of solar masses) there will be a "snow line" in the disk, beyond which ice would be able to form. So, it seems quite plausible that the centre of our galaxy is aswarm with blanets, many much like our own Earth, with quite possibly conditions suitable for life. Imagine the view! www.space.com/black-hole-planets-blanets.html
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Post by user211 on Aug 7, 2020 17:07:32 GMT
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Post by jandl100 on Aug 10, 2020 15:59:35 GMT
Another article on blanets - possible planets around some supermassive black holes at the centres of galaxies. "Astronomers are speculating that planets by the thousands may be orbiting in a “safe zone” captured by the massive gravitational force of these paradoxical, terrifying, “perfectly constructed” spacetime objects. In 2019, Harvard’s Avi Loeb and NASA’s Jeremy Schnittman, suggested that inhabited planets might exist around the black holes harbored at the center of most galaxies similar to the fictional waterworld planet orbiting the supermassive black hole Gargantua in the movie Interstellar. It’s possible, they suggested, that extreme forms of life life may form on some of these planets." dailygalaxy.com/2020/08/exist-at-an-astonishing-scale-planets-orbiting-black-holes-could-harbor-life-beyond-extreme/
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Post by MartinT on Aug 10, 2020 17:12:46 GMT
Wouldn't the x-ray emissions be too high for much in the way of life forms?
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Post by jandl100 on Aug 10, 2020 18:11:52 GMT
Wouldn't the x-ray emissions be too high for much in the way of life forms? For typical SMBHs of billions of solar masses, that's true, it would be a very hostile environment in the 'habitable zone' as usually defined by temperature. But for galaxies like the Milky Way which for whatever reason have small or less active SMBHs [our SMBH being a mere 4 million solar masses] it would be a much more benign environment and conditions in the habitable zone could be broadly OK for life as we know it.
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Post by jandl100 on Aug 11, 2020 8:04:00 GMT
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Post by Firebottle on Aug 13, 2020 6:50:46 GMT
Fascinating.
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Post by jandl100 on Aug 13, 2020 9:23:35 GMT
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Post by jandl100 on Aug 13, 2020 11:52:20 GMT
High speed stars in close orbit around the super massive black hole at the centre of our galaxy. "We Just Found The Fastest Star in The Milky Way, Travelling at 8% The Speed of Light" ... On its orbital journey, S4714 reaches a velocity of around 8 percent of the speed of light - an absolutely jaw-dropping 24,000 kilometres per second (15,000 miles per second). But that's not even the most amazing thing. S4714 ... has given us the first candidate for a type of star originally proposed nearly 20 years ago - those that get so close to a black hole, they are 'squeezed' by its tidal forces. They're also known as 'squeezars'. www.sciencealert.com/the-fastest-star-in-the-galaxy-zooms-as-high-as-8-percent-of-the-speed-of-light
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Post by MartinT on Aug 13, 2020 12:35:15 GMT
The relativistic effects must be astonishing. I wonder how closely it approaches the event horizon?
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Post by MartinT on Aug 13, 2020 12:44:06 GMT
What did Voyager-2 see on Uranus last?
Bear with it, it gets really interesting further in.
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