astronomy | Recent Entries

Looks like a "Serpens-Sagittarius Spur" newly recognized as such based on Phil Plait's commentary today here:

https://www.syfy.com/syfywire/newly-discovered-structure-in-the-milky-way

Opinions?

Current Mood: curious

dewline

Admittedly, this is from the official ESA Flickr account, so...they've got something to promote, and I think it's worth promoting.

I want to see hardcopy "looking down along the Z-axis" maps, to be honest.

Current Mood: nerdy

dewline

Is anyone here using this software?

https://zah.uni-heidelberg.de/institutes/ari/gaia/outreach/gaiasky/

Current Mood: hopeful

dewline

Sourced from

coudal_feed:

https://www.instagram.com/p/B8uNIVDJjif/

Current Mood: busy

dewline

For people wanting to keep an eye on that particular star via Twitter:

https://twitter.com/betelbot

Current Mood: busy
Current Music: The House, on CBC Radio

dewline

Anyone else keeping this bookmark on their browser(s)?

https://twitter.com/hashtag/gaiadr2?f=tweets&vertical=default&src=hash

seasonoftowers

The image is all over the 'net, but thought I'd also link to the papers, and the soon-to-happen Reddit AMA

You know shit's good when you need to correct for the drift of the polar ice cap so that the components of your radio telescope network (one of which is located in Antarctica) stay in sync and continue acting like a single giant radio telescope the size of the goddamn planet.

steorra

It seems like we've found a moon orbiting an extrasolar planet. The moon is approximately Neptune-sized and the planet is approximately Jupiter-sized (which could cover a large range of masses, because once things get about as massive as Saturn they mostly get denser rather than bigger when you add more mass, until they hit star size.)

Large Exomoon Likely Orbits a Faraway World

Teachey and Kipping found that two aspects of the transit data from Hubble were consistent with their exomoon hypothesis. First, the planet transited the star 1.25 hours earlier than expected on the basis of the orbital period measured by Kepler. “That is indicative of something gravitationally tugging on the planet” during this particular transit, Kipping explained.
[...]
Second, the Hubble observations of the host star’s brightness showed two dips in brightness instead of just the one from the planet. “The location, shape, and depth of this event appear consistent with a Neptune-sized moon [also] transiting in front of the star,” Kipping said. The team also saw this secondary dip in the star’s light in some of the Kepler transits.

I wonder if they'll be able to infer enough information about the exomoon's orbit to work out anything about the masses of the planet and moon. I'm guessing likely not, but it is impressive how much information astronomers are able to squeeze out of seemingly tiny amounts of data, so maybe.

steorra

Charon’s icy surface erupted from an underground ocean

So the more plausible explanation is that the underground ocean escaped overground, allowing an icy slush to flood out over Vulcan Planitia. This could have occurred through cryovolcanism, the ice version of normal volcanoes. But these weren’t violent, Krakatoa-style eruptions. Instead, they would have been a slow creep of material through cracks in Charon’s surface.

A slightly more dramatic version of this slow flood depends not on small cracks, but on large-scale rupturing of Charon’s upper layers. In this scenario, the surface doesn’t just crack, but founders into huge chunks which sink or tilt into the slushy ocean.

This would have probably caused a faster flooding, but the end result looks identical as far as New Horizons’ images can show.

steorra

(Cross-posted to my own journal)

There's a neat post by Emily Lakdawalla about "Some big moons in the Kuiper belt" It's a year old, but I just read it recently.

It talks about how Eris's moon Dysnomia and Orcus's moon Vanth are bigger than previously thought. This means that they are also darker in colour than previously thought - a bigger surface must be darker-coloured to produce the same brightness from earth that we see.

This ends up meaning that Eris and Dysnomia are almost opposites in brightness: Eris reflects 99% of the light that falls on it, while Dysnomia reflects around 4%, making it darker than coal!

steorra

I happened upon this neat quiz by the amazing Emily Lakdawalla. There are pictures of the surfaces of 18 solid solar system worlds, all to roughly the same scale of 1 km/pixel, and you can try to guess which picture is which world. Some are pretty easy if you've spent much time looking at space imagery, and some are quite difficult.

The answers are here.

seasonoftowers

Hello, and hope I'm not too off-topic with stargazing gear discussion, but does anyone have any recommendation for a good 15mm 1.25' aperture telescope eyepiece? Looking for usability with glasses, good performance on a f5 telescope and non-Televue/Pentax prices, preferably

Thanks!

steorra

Lights On | Lights Out

This piece has some nice graphics and discussion of changes in nocturnal satellite images of Earth between 2012 and 2016. There's a slider where you can compare two maps directly, as well as processed images showing increased lighting in blue and decreased lighting in pink.

thewayne

I'm not a man of wealth and fame. My main interest in astronomy is the fact that I'm married to an astronomer: I do enjoy astronomy, I'm just not a scientist. My wife operates the 3.5 meter telescope at Apache Point Observatory, and also runs the APOLLO lunar laser ranging experiment (got some good results last night in marginal weather). And she is famous, at least in some circles: she was the final segment of the Mythbusters episode in 2008 debunking the 'man has never been to the moon' garbage, along with several other TV programs.

We're hoping to head up to Oregon to see the solar eclipse this year, we'll see what happens. I had hoped to buy a solar telescope to take some photos of it, but I've been unemployed for about 10 months now, so that's not too likely. Maybe I can kitbash something together.

If you like big telescope pictures, or are interested in a video that I made about the lunar laser ranging conducted at APO, I have a photography web site. I need to upload a couple of photos of the Clark telescope at Lowell Observatory that I shot in February, unfortunately the Pluto Discovery Telescope and dome are closed for a refurb. I'm hoping next year to be able to get some fresh photos of them.

thewayne

I saw this on Slashdot this morning, I wonder how long it will take to integrate the data and start producing results.

Earth-Sized Telescope Set To Snap First Picture of a Black Hole (newscientist.com) 52

Posted by msmash on Friday April 07, 2017 @08:40AM from the big-picture dept.

An anonymous reader writes from a New Scientist report: This week, we will have our first chance to take a picture of the supermassive black hole at the centre of our galaxy. The image could teach us how black holes work and even how the largest and smallest forces governing the universe fit together. The Event Horizon Telescope is switching on. It consists of eight radio observatories around the world, including telescopes in Spain, the US and Antarctica. And for just four or five nights between 5 and 14 April, if the weather is clear at all of the observatories, they will all turn on at once. Each telescope will point at Sagittarius A, the supermassive black hole at the centre of the Milky Way, and measure every radio wave coming from its direction. Linking together observatories spread across such a huge area and combining their observations to filter out extra light will effectively create a powerful "virtual telescope" almost the size of Earth. These telescopes will together capture sharper and more detailed data than we've ever had from Sagittarius A, which we still know very little about, as well as the larger black hole at the centre of nearby galaxy M87. With the telescopes generating a total of 2 petabytes of data per night -- enough to store the full genomes of some 2 billion people -- astronomers hope to take the first image of the event horizon around a black hole, and the bright matter hurtling around it.

dewline

Subjects of interest:

1. Kepler 1649b
2. GJ 1132b

Current Mood: curious

steorra

Back in October I wrote about Alpha Centauri B's first known planet, and associated discoveries about Alpha Centauri B. I talked about all the work that went into filtering out noise (redshift and blueshift from other sources) to find the signal from the planet.

Well, that was a very complex process, and some work since then has followed up and suggests that it may have gone awry, and there may not be a planet after all. Here's an article with more info:
No Planet of Alpha Centauri B?

It doesn't conclude for sure that there is no planet, but it casts doubt on the idea that there is; ultimately, more data will be needed to resolve the issue, and we might have to wait a while for that data, since the orbits of Alpha Centauri A and B are bringing them closer together in the sky from our point of view, which will make it impossible to study just the light of Alpha Centauri B without some light from Alpha Centauri A getting mixed in.

steorra

Cassini spots mini Nile River on Saturn moon

Cassini's radar imaging of Titan has spotted evidence for a 400 km long river on Titan, with its mouth in a lake. Lakes and rivers on Titan are made of liquid methane/ethane, not water, which is frozen rock-like at Titan's temperatures. The riverbed-shaped structure is apparently full of liquid, not a dry empty riverbed, because it appears dark to the radar, indicating that it has a smooth surface.

I'm not sure why it's compared specifically to the Nile river.

steorra

A piece of big astronomy news came out yesterday: An earth-sized planet has been discovered orbiting Alpha Centauri B, a relatively sun-like star (a bit smaller and fainter than the Sun) in the nearest star system to the Sun. The planet is not particularly earth-like, though, since it orbits the star in only about 3.2 days, and thus would be extremely hot.

I started to write a long entry talking about Alpha Centauri system the system and the discovery, but I think instead I'm going to link a few articles - there are many more that could easily be found - and talk a bit about some things I noticed in reading the original paper.

( News stories )

( Links to the original paper )

I gave the paper a quick reading, and while some of it was too technical for me to understand, I was able to follow the basics of it. And I was once again amazed by the amounts of information that astronomers are able to squeeze out of apparently tiny amounts of data - in this case, the spectrum of a star observed repeatedly over time.

( Details )

Here's an article that talks about some of the noise sources in non-academic terms.

steorra

I posted about a week ago about a double meteor sighting on September 21st where calculations seemed to show that they were in fact the same object which had once skimmed through Earth's atmosphere, then out again, then gone around the earth and re-entered the atmosphere.

Other/newer calculations are showing that that seems not to have happened after all. Instead, it seems like it really was just two independent fireballs.

I'm not sure the question is 100% resolved yet. Science takes time.