astronomy

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This was last night:

And this was just before sunset tonight:

From the Mt. Wilson Observatory website:

Mount Wilson Observatory Status

Angeles National Forest is CLOSED due to the extreme fire hazard conditions. To see how the Observatory is faring during the ongoing Bobcat fire, check our Facebook linkTwitter link, or go to the HPWREN Tower Cam and click on the second frame from the left at the top, which looks east towards the fire (also check the south-facing cam and the recently archived timelapse movies below which offer a good look at the latest events in 3-hour segments. Note to media: These images can be used with credit to HPWREN). For the latest updates on the Bobcat fire from U.S. Forest Service, please check out their Twitter page.

Last night the firefighters set a strategic backfire to make a barrier to the fire on our southern flank. To many of us who did not know what was happening it looked like the end. Click here to watch the timelapse. The 12 ground crews up there have now declared us safe. They will remain to make sure nothing gets by as the fires tend to linger in the canyons below. They are our heroes and we owe them our existence. They are true professionals, artists with those backfires, and willing to put themselves at considerable risk to protect us. We thank them!!!!

There will be plenty of stories about how the Observatory and the many broadcast transmitters nearby were saved from the Bobcat Fire. For the curious, start with these links:

I’ll add some more soon.

Across almost 73 laps around the Sun, I’ve seen six notable comets. The fifth was Hale-Bopp, which I blogged about here, along with details on the previous four, in 1997. The sixth is NEOWISE, and that’s it, above, shot with my iPhone 11. There are a couple other shots in that same album, taken with my Canon 5D Mark III. Those are sharper, but this one shows off better.

Hey, if the comet looks this good over the lights of Los Angeles, you might have a chance to see it wherever you are tonight. It’ll be under the Big Dipper in the western sky.

Every night it will be a bit dimmer and farther away, so catch it soon. Best view is starting about an hour after sunset.

 

 

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To answer the question Where are SiriusXM radio stations broadcasted from?, I replied,

If you’re wondering where they transmit from, it’s a mix.

SiriusXM transmits primarily from a number of satellites placed in geostationary orbit, 35,786 kilometres or 22,236 miles above the equator. From Earth they appear to be stationary. Two of the XM satellites, for example, are at 82° and 115° West. That’s roughly aligned with Cincinnati and Las Vegas, though the satellites are actually directly above points along the equator in the Pacific Ocean. To appear stationary in the sky, they must travel in orbit around the Earth at speeds that look like this:

  • 3.07 kilometres or 1.91 miles per second
  • 110,52 kilometres or 6,876 miles per hour
  • 265,248 kilometres or 165,025 miles per day

Earlier Sirius satellites flew long elliptical geosynchronous orbits on the “tundra“ model, taking turns diving low across North America and out into space again.

Satellites are also supplemented by ground repeaters. If you are in or near a site with repeaters, your Sirius or XM radio may be tuned to either or both a transmitter in space or one on the ground nearby. See DogstarRadio.com’s Satellite and Repeater Map to see if there is one near you.

In addition, SiriusXM also streams over the Internet. You can subscribe to radio, streaming or both.

As for studios, those are in central corporate locations; but these days, thanks to COVID-19, many shows are produced at hosts’ homes. Such is the case, for example, with SiriusXM’s popular Howard Stern show.

So, to sum up, you might say SiriusXM’s channels and shows are broadcast from everywhere.

I should add that I’ve been a SiriusXM subscriber almost from the start (with Sirius), and have owned two Sirius radios. The last one I used only once, in August of 2017, when my son and I drove a rental minivan from Santa Barbara to Love Ranch in central Wyoming, where we watched the solar eclipse. After that it went into a box. I still listen a lot to SiriusXM, almost entirely on the phone app. The rest of my listening is over the Web, logged in through a browser.

Item: a few days ago I discovered that a large bill from SiriusXM was due to a subscription for both the radio and the Internet stream. So I called in and canceled the radio. The subscription got a lot cheaper.

I bring this up because I think SiriusXM is a single example of a transition going on within the infrastructure of what we still call radio, but instead we would call streaming if we started from scratch today. We would call it streaming because that’s how broadcasting looks like on the Internet. And the Internet is subsuming and gradually replacing over-the-air radio with what for most purposes is a better system. When it’s done, most or all of over-the-air radio will be gone.

In The Intention Economy (Harvard Business Review Press, 2012), I saw this future for what we wouldn’t call television if we started that one from scratch today (or even when this was published, eight years ago):

Intention Economy chart

Today we’d put Netflix, Amazon Prime, YouTube TV and Apple TV in the upper left (along with legacy premium cable staples, such as HBO and Showtime). We’d put PBS stations there too, since those became subscription services after the digital transition in 2008 and subsequent spectrum sales, which reduced over-the-air TV to a way for stations to maintain their must-carry status on cable systems. (Multiple “repacks” of TV stations on new non-auctioned channels have required frequent “re-scans” of signals on TVs of people who still want to watch TV the old-fashioned way and hook up an antenna.)

While over-the-air radio has been terminal for years, its death has been less hastened by regulatory changes to satisfy the need for more data-friendly frequencies (which TV has, and radio doesn’t). Here’s the diagnosis I published in 2016. I’ve also been keeping a photographic chronicle of radio in hospice, over on my Flickr account for Infrastructure. A touching example of one station’s demise is Abandoned America’s post on the forgotten but (then) still extant studios of WFBR (1924-1990) in Baltimore.

The main difference with radio is that it still wants to be free.

Want to have some fun with that? Go to RadioGarden and look around the globe at free streams from everywhere. My own current fave is little CJUC in Whitehorse, Yukon. (I list others here.) All of those are what we say is “on” the Internet. But where is that?

We can pinpoint sources in the physical world, as RadioGarden does, on a globe; but the Internet defies prepositions, because there is no “there” there. There is only here, where we are now, in this non-place with no distance and no gravity because its nature is to defy both, leaving those up to the individual. I’m in Santa Barbara right now, but could be anywhere. So could you.

On the Internet, over-the-air TV and radio are anachronisms, though charming ones. Like right now, as I’m listening to Capricorn FM from Polokwane, South Africa. (“Crazy up-tempo hip-hop” is the fare.) But I’m not listening on a radio, which would require tuning to 89.9fm somewhere within range of the station’s transmitter. I’m here, on (or in, or through, or pick-your-preposition) the Internet.

A few years ago my then-15-year-old son asked me what the point of “range” and “coverage” was for radio stations. Why, he wondered, were those features rather than bugs? Meaning why is it okay for a station to fade away as you drive out of town?

His frame of reference, of course, was the Internet. Not the terrestrial world where distance and the inverse square law apply.

Of course, we will always live in the terrestrial world. The Internet may go away, or get fractured into regions so telecom companies can bill for crossing borders and governments can limit what’s accessible within those borders. But the Internet is also an infrastructural genie that is not going back in the bottle. And it is granting many wishes, all in a new here. It exists in the manner of a natural law, such as we have with gravity in the physical world.

And I submit that we are still only starting to understand it. (For how we’re only starting, see here.)


This post first appeared in a sister blog, Trunk Line.

Source: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)

Pillars of Creation” is a live view of stars forming in a neighboring region of the Milky Way. (Inside the Eagle Nebula, 5,400 to 6,100 light years away.)

The Solar System, formed 4.6 billion years ago. Earth became a planet .46 billion years later. That was 9.247 billion years after the Big Bang, which happened 13.787 billion years ago, meaning that our solar system is more than a third of the age of the Universe. (By the giant impact hypothesis, Earth was enlarged 4.5 billion years ago when it mooshed together with another planet about the size of Mars. That ex-planet is now called Theia, and the leftover material it scattered into space is now the Moon. Another gift to Earth, says the theory, is our water.)

Hydrogen, helium, and other light elements formed with the Big Bang, but the heavy elements were cooked up at various times in the 8 billion year span before our solar system was formed. Some, perhaps, are still cooking.

Life appeared on earth at least 3.5 billion years ago.* Oxygenation sufficient to support life as we know it happened at the start of proterozoic era, about 2.5 billion years ago. The phanerozoic eon, characterized by an abundance of plants and animals, began 0.541 billion years ago and will continue until the Sun gets so large and hot that photosynthesis as we know it becomes impossible. A rough consensus within science is that this will likely happen in just 600 million years, meaning we’re about 80% of our way through the time window for life on Earth.

More perspective: the primary rock formation on which most of Manhattan’s ranking skyscrapers repose—Manhattan Schist—is itself about a half billion years old. (My ass is three floors above some right now.)

In another 4.5 billion years, our galaxy, the Milky Way, will become one with Andromeda, which is currently 2.5 million light-years distant but headed our way on a collision course, looking for now like a thrown frisbee, four moons wide. (It’s actually much larger.) The two will begin merging (not colliding, because nearly all stars are too far apart for that) around 4 billion years from now, and in about 7 billion years will complete a new galaxy resembling an elliptical haze. Here is a video simulation of that future. And here are still panels for the same:

Our Sun will likely be around for all of that future, though by the end it will have become a red giant with a diameter wider than Earth’s orbit, or perhaps will have gone nova, surviving as a white dwarf. (Also—I’m adding this later—Andromeda is weird and scary.)

When that’s done, the Universe will be about 16 billion years old. Or young. In TIME WITHOUT END: PHYSICS AND BIOLOGY IN AN OPEN UNIVERSE, Freeman Dyson gives these estimates for the future age of the Universe:

TABLE I. Summary of time scales.

Closed Universe
Total duration 10^11 yr

Open Universe
Low-mass stars cool off 10^14 yr
Planets detached from stars 10^15 yr
Stars detached from galaxies 10^19 yr
Decay of orbits by gravitational radiation 10^20 yr
Decay of black holes by Hawking process 10^64 yr
Matter liquid at zero temperature 10^65 yr
All matter decays to iron 10^1500 yr
Collapse of ordinary matter to black hole
[alternative (ii)] 10^(10^26) yr
Collapse of stars to neutron stars
or black holes [alternative (iv)] 10^(10^76) yr

So the best guess here is that Universe is about 1% into its lifespan, which has a great many zeros in its number of birthdays. In biological terms, that means it’s not even a baby, or a fetus. It’s more like a zygote, or a blastula.

So maybe… just maybe… the forms of life we know on Earth are just early prototypes of what’s to come in the fullness of time, space, and evolving existence.

Bonus link: Katie Mack, who has forgotten more about all this than I’ll ever know.

[Later…] *Make that 4.1 billion years ago.

[Later again…] Then there is this.


Walked out on the front deck this morning and grabbed a photo set of the Moon between conjunctions with Venus (that was yesterday), Jupiter (tonight and tomorrow) and then Mercury (Saturday), before passing next to the Sun as a new moon on Sunday.

More about the show at EarthSky. Get up early and check it out.