This view of Comet LINEAR shows it to be 100 times righter than expected. See http://www.space.com/32376-how-to-se...ekly_2016-3-25. See the post on Space.com for more information.
Printable View
This view of Comet LINEAR shows it to be 100 times righter than expected. See http://www.space.com/32376-how-to-se...ekly_2016-3-25. See the post on Space.com for more information.
It has been overcast, but I am hoping to see this before it fades away. Also I was expecting to see this in the evening, but it looks like the morning is the best time.
Here's a new video on Ceres: https://www.youtube.com/watch?v=AtLdprhvtVE
This post on multiverses is interesting: http://www.space.com/32452-can-scien...ultiverse.html. I like ideas that turn to dominant theories of the day on their heads.
EarthSky reports that Cassini which has been orbiting Saturn for over 10 years cannot detect any effects of the 9th planet that can't be explained by what they know already: http://earthsky.org/space/planet-9-n...sini-at-saturn.
It is easy to believe everything we hear and that's why it is good to hear arguments against an hypothesis. We can't check all this ourselves.Quote:
Originally Posted by Dreamwoven
These are interesting. At the moment I think I agree with Bas van Fraassen's strict empiricism as a limit for science. When one gets to speculations, the philosophers should take over. This might help the rest of us when we assess what actually has data to back it up and what only has logic.Quote:
Originally Posted by Dreamwoven
http://www.space.com/32523-keplers-n...an-worlds.html. Quite an interesting discussion of orphan worlds.
I noticed that the K2 project searching for orphan planets is only going to last three months. I guess if they don't find something using the microlensing technique in that time, the technique may need to be refined before continuing. There may be some other reason the project is so short.
That is probably the case.
This is interesting, how a star can strip away a planet's atmosphere.
http://earthsky.org/space/stars-stri...f-super-earths
These exoplanets are likely close to their stars.
Certainly they are, the comparison can still be made to Mercury or even Venus. They may well have had life-encouraging atmospheres in their early days.
This post suggests there have been problems with Kepler, which may account for the uncertain nature of the observations, as Kepler was not working for about a week: http://earthsky.org/space/kepler-is-...from-emergency
The K2 mission using gravity sounds like an interesting way to detect these exoplanets. I guess the previous technique was to see if planets made a transit of their stars.
Thee is a lot happening right now. See this project to launch postage-stamp sized probes to our nearest galaxy, Alpha Centauri. Sure, its all just hype and publicity, only taking 10 years to make the journey. The comments are more informed and interesting than the article!
http://www.space.com/32546-interstel...-starshot.html
Or 3 days to Pluto: http://www.space.com/32558-starshot-...ar-system.html
It looks like they are getting smaller. I think you posted a link about small probes earlier, but not as small as postage stamps. The ultimate in size would be to send just a laser beam out and see what bounces back. I suspect this is sort of done now with determining the distance from the earth to the moon by having a beam bounce off a retroreflector we placed there, either with humans or robots, during the moon missions.
Its going to take a while before this project is launched, and then another 10 years before it arrives, I doubt I will still be around in 2035. But its fascinating how fast changes work!
I got up in the middle of the night and noticed the Moon, Jupiter, Mars and Saturn across the sky through my window. They were the brightest objects out there with all the urban lighting. It made me realize how obvious these would have appeared to our ancestors looking up at the sky.
I've not seen these, the nights are too cloudy, but I'm sure you are right.
Sweden has its own space program, and its own space magazine - Populär Astronomi, that is published Quarterly. The centre for the research is in Kiruna, in the far north, where there is a rocket launch site. The Milky Way is called the Winter Street (vintergatan), same idea different language. There is a study to investigate the oldest stars in the galaxy, all near its centre.
I am still a member of the Society for Popular Astronomy and this is an extract from one of their email bulletins, much interesting stuff:
Society for Popular Astronomy [email protected]
11:14 (31 minutes ago) to me
The SOCIETY for POPULAR ASTRONOMY
Electronic News Bulletin No. 420 2016 April 17
Here is the latest round-up of news from the Society for Popular Astronomy. The SPA is arguably Britain's liveliest astronomical society, with members all over the world.
YOUNG, UNATTACHED 'JUPITER' FOUND IN SOLAR NEIGHBOURHOOD
Carnegie Institution for Science
A team of astronomers has discovered one of the youngest and brightest free-floating planet-like objects in reasonably close proximity to the Sun. At an age of only 10 million years, the object identified as 2MASS J1119-1137 is between four and eight times the mass of Jupiter, and hence falls in the mass range between a large planet and a small brown-dwarf star. From data obtained by WISE and other ground-based telescopes, 2MASS J1119-1137 was identified by its unusual colours: it emits much more light in the infrared part of the spectrum than would be expected if it had already aged and cooled. The challenge of identifying such rare objects is distinguishing them from a multitude of potential interlopers. Much more commonly, distant old and red stars residing in the far reaches of our Galaxy can display the same characteristics as nearby planet-like objects. When the light from the distant stars passes through the large expanses of dust in our Galaxy on its way to our telescopes, it gets reddened, so those stars can pose as potentially exciting nearby young planet-like objects when actually they are not that at all. With knowledge of such common misidentifications, the team immediately checked its findings using the FLAMINGOS-2 spectrograph instrument on the Gemini South telescope in Chile. It promptly confirmed that 2MASS J1119-1137 is in fact a young low-mass object in the solar neighborhood, and not a distant reddened star.
Next, the team wanted to determine the age of the object. Gemini observations showed only that the object was younger than about 200 million years. If it were much younger, it could actually be a free-floating planet -- an analogue of our own Jupiter, yet without a host star. The final piece of the puzzle was contributed by the FIRE spectrograph on Carnegie's 6.5-m telescope in Chile. FIRE measured the line-of-sight velocity of 2MASS J1119-1137. Combining that measurement with the sky motion of 2MASS J1119-1137, the team discovered that it belongs to the youngest group of stars in the solar neighbourhood. That group contains about two dozen 10 million-year-old stars, all moving together through space, and is collectively known as the TW Hydrae Association. Being 'nearby', 95 light-years away, 2MASS J1119-1137 only narrowly misses being the brightest free-floating planet analogue. That position is held by another object known as PSO J318.5−22, discovered three years ago. However, at an age of 23 million years, PSO J318.5−22 is more than twice the age of 2MASS J1119-1137, and is more massive. Discovering free-floating planet analogues like 2MASS J1119-1137 and PSO J318.5−22 offers an opportunity to study giant planets outside the Solar System, because free-floating planet candidates are much easier to scrutinize than planets orbiting around other stars. Objects like 2MASS J1119-1137 are drifting in space all alone and our observations are not overwhelmed by the brightness of an adjacent host star.
This is just one item in a list of news items.
It is good to have something like this relatively nearby to study. Just how far away is 95 light years relative to other objects in the universe? How large is the solar neighborhood?
A light year takes one year at the speed of light to cover. Nothing apart from light travels that fast. This is one estimate from http://www.universetoday.com/75691/h...the-milky-way/, take 100,000 light years from one end to the other.
Querying the internet, the Andromeda galaxy is 2.5 million light years away. As you mentioned, our galaxy is 100,000 light years across. Alpha Centauri is 4.4 light years away. So these objects at 95 light years away still seem quite far from us. I wonder how big the sun's local neighborhood is? I suppose that could be some arbitrary number say 100 or 200 light years.
I guess Alpha Centauri (about 4 light years away) is close enough to hope those postage stamp size probes would be able to make the journey in a reasonable time.
Yes, as you say, we still haven't properly explored our own sun's local neighbourhood. We are still not even sure what planets there are, and only done preliminary scans of some of the ones we do know. Mars is probably the best explored, but again only very preliminary.
Today, Space.com came up with this interesting post on planets going round stars:
http://www.space.com/32623-stars-wob...exoplanet.html
It looks like Gliese 832c may not be "Earth 2.0" as previously thought.
I guess we will eventually know whether we have a new planet or two in orbit round the sun.
http://earthsky.org/space/watch-nasa...pace-telescope
This is the next generation of space telescopes currently being built.
This is about the moon recently discovered going round the dwarf planet MakeMake, spotted by Hubble: http://_source=EarthSky+News&utm_cam...3cd8-394044013
http://earthsky.org/space/watch-nasa...pace-telescope
This is the next generation of space telescopes currently being built.
This is about the moon recently discovered going round the dwarf planet MakeMake, spotted by Hubble: http://_source=EarthSky+News&utm_cam...3cd8-394044013
Its got a long url, I hope it works!
I watched the video in the first link. I liked the phrase "universe's first light" used there. I was not able to access the second link.
The second link is not accessible for me either.
EarthSky is about how the Oort Cloud got its name: a Dutch astronomer in 1950: http://earthsky.org/space/jan-oort-b...ons-oort-cloud.
It is interesting that the existence of the Oort cloud is still considered a theory, but those comets have to come from somewhere.
The problem is that the Oort Cloud is itself a concept rather than proven fact. It covers a huge area of space, See https://en.wikipedia.org/wiki/Oort_cloud
Extract from Society for Popular Astronomy:
Oddly enough Gaia is not described in Wikipedia. Definitely a miss as Gaia was launched in 2013:
Saturday’s London meeting: Gaia – the Milky Way and Beyond
It sounds like something from Star Trek: ‘Its five-year mission – to seek out new worlds, to reveal cataclysms deep in the Universe, and to discover strange objects that as yet we can’t even understand.’ But this is not the Starship Enterprise, it is the European Space Agency's flagship Gaia mission, launched in 2013. It will produce the most accurate three-dimensional map of our own galaxy, the Milky Way. As well as surveying millions of stars throughout the Galaxy, Gaia will reveal transient events taking place far out in the rest of the Universe, including stars exploding as supernovae and being swallowed by black holes.
Our main speaker, Dr Morgan Fraser of Cambridge University, will explain how Gaia will achieve its amazing precision measurements, and give us a taste of some of the science highlights so far.
Following the break, Robin Scagell will look at some of the highlights in the sky for the next three months, including the Transit of Mercury. Comet Section Director Stuart Atkinson will speak about Comets: Fear, Fact and Fiction and discuss why comets have been blamed for so many disasters in history, plus taking a look at the Rosetta mission.
The meeting is open to all SPA members and friends, and begins at 2 pm this coming Saturday, 30 April. The venue is the Khalili Lecture Theatre of the School of Oriental and African Studies, near Russell Square, London WC1H 0XG. The nearest tube station is Russell Square. For a map of the location and more details, go to the SPA website.
In all of these studies I wonder what the precision is of the measurements including a measure of the margin of error. On top of that is how those results are obtained.Quote:
Originally Posted by Dreamwoven
I think this has to be two questions that should hopefully be answered at the session. Information on Gaia seems to be very sparse.
Repeating bursts of radio waves from mysterious object (from an article in Popular Astronomy): "Fast Radio Bursts" (FRB) from outside the Milky Way have been noted since they were first discovered in 2001. See https://en.wikipedia.org/wiki/Fast_radio_burst. They remain an unexplained mystery.
That was the first I heard of fast ratio bursts. But there is a lot I haven't heard of. It appears they are still rare. It looks like they come in a repetitive fashion which is probably what makes them stand out.