Anyone for an astronomy thread?

[Rogin the Armchair fan]

The "live coverage of the landing" was underwhelming, to say the least. It was a Bollywoodish cartoon animation of the lander, with actual Modi waving a little flag and giving a hugely protracted speech. Is there live feed from, er, the actual moon, yet?

[Discordant Resonance]

Following the failure of the Russian launcher last week, India has now landed a spacecraft on the Moon, though you'd imagine they're still decades away from a manned mission.

[Sits]

Down here, Venus and Mars have been so close for the past week or so, they are forming a weird shape in the sky. Combined with a star close by they almost make a cup shape and you begin to understand how the stories from history of chalices in the heavens might have come about.

[Discordant Resonance]

Venus is already clearly visible against the new moon, and seemingly Mars will appear between the two later, once the sky darkens.

[The Awesome Berbaslug!!!]

I saw three of these about a fortnight ago. two planets seemingly orbiting the moon

[Nocturnal Submission]

Keep 'em peeled: https://www.bbc.co.uk/news/science-environment-65056407

[San Bernardhinault]

It’ll be no bigger than a chihuahua’s head by the time it gets through the atmosphere.

[The Awesome Berbaslug!!!]

An asteroid the size of a minibus will pass South America closer than our own man-made satellites later tonight.

But surely we have known about this for a while you might think? Haven't we got the technology to blast asteroids now after that whole fanfare over the successful DART / dimorphos mission? Well, we started planning the DART mission in 2015, so a mere seven years notice needed. We found out about this asteroid last weekend, when an amateur astronomer noticed it.

I, for one, feel very reassured about our planetary defence capabilities.

https://www.bbc.co.uk/news/science-environment-64411469

I wouldn't worry too much balders, an asteroid that size is going to be little more than glowing dust after a few seconds contact with the earth's very upper atmosphere. They're not really looking for stuff like this, because it's far too small to waste resources on, and it being so small makes it hard to see until it gets really close. that article suggests that they're fairly confident that they have a good grasp on where nearly all of the planet killers are, they're a bit sketchy on a lot of the city killers though.

Also I wouldn't necessarily take the timeline of the Dart mission as a guideline for how long it would take to put together a mission to hit an asteroid, if they really wanted to do something about it. They only spent about $400 million on the whole thing, which is a minuscule sum for doing something in space. The reason it took so long is that they dripped out the money at a rate of about $40 million dollars a year before they splashed out an extra bit to actually launch the thing. Ultimately they hit an object about two football fields in size, from 11 million kilometres away, at first time of asking, with a six hundred kilo bullet, and messed it right up, changing the orbit of the little asteroid, and the big asteroid by quite a lot. Had this thing been on a course for earth, it would have done the job, by a massive margin. The tricky bit was getting it right first time on a tiny budget. If they needed to do it again it would take weeks to get together, rather than seven years.

Though I would feel a little more comfortable if we knew where the missing 60% of city killing asteroids were, because if you know where they are, you can tell a very long time in advance if they're going to come close to the earth, and when, and the more advance warning you have, the easier it is to do something about it, because the effect of hitting them is cumulative over time, and the further out you can hit them, the less you have to do to them, in order to achieve the required effect.

[hobbes]

I was just going to suggest the Planck length.

[Ginger Yellow]

s there one that's independent we can use for when the "others" are involved in "first contact", he says, shifting the goalposts

At a micro scale, there's the Planck length I suppose. Or you could use the size of atoms/subatomic particles, though that would be imprecise I would have thought. At a macro scale, in particular given the expansion of the universe it's hard to think of one that isn't going to be in some way shaped by our own dividing up of time. The second, at least, is defined in a way that we can (theoretically) communicate to "others" and have them come up with the same result.

The only thing I can think of is if there's some physically determined limit to size of something that we can be confident would be consistent across the universe. But that seems a lot wobblier than just using the speed of light.

[Ginger Yellow]

Also, strictly speaking, a light year is 31,577,600 light seconds, so not technically reliant on Earth, though obviously it is derived from the Julian calendar

[Guy Profumo]

I think I get what you're saying, but it's only Earth-related because of the unit of time you've chosen. Light second is independent of the Earth.

Thanks!

That'll be the boy!

So are there terms for massive multiples of light seconds
(Though we've defined the second on our own biases, is there one that's independent we can use for when the "others" are involved in "first contact", he says, shifting the goalposts)

[Ginger Yellow]

light year

I think I get what you're saying, but it's only Earth-related because of the unit of time you've chosen. Light second is independent of the Earth.

[Guy Profumo]

I'm sure I've asked this before, but…


Is there an astronomical measure of distance which doesn't rely on the Earth as a reference)

(i.e. not AU, light year, Parsec)

?

[torres]

There’s a comet visible at the moment just near the handle of The Plough. I attempted spotting it last night but the sky was too bright. Tonight looks a better bet for it.

[Balderdasha]

An asteroid the size of a minibus will pass South America closer than our own man-made satellites later tonight.

But surely we have known about this for a while you might think? Haven't we got the technology to blast asteroids now after that whole fanfare over the successful DART / dimorphos mission? Well, we started planning the DART mission in 2015, so a mere seven years notice needed. We found out about this asteroid last weekend, when an amateur astronomer noticed it.

I, for one, feel very reassured about our planetary defence capabilities.

https://www.bbc.co.uk/news/science-environment-64411469

[Discordant Resonance]

Impossible to miss Mars in the sky tonight, as it literally appears as though it were above the moon.

[San Bernardhinault]

All Y’all mocked my hot tub. But I saw a Geminid last night and two tonight! Without freezing to death.

Meanwhile watching the Orion capsule retuning to earth felt so very, very retro. After decades of shuttles or Muskrockets returning in one reusable piece there was a conical top-of-the-rocket capsule floating down with three parachutes and a bunch of inflatable flotation balloons on top and it was like we were back in 1972 and I was 1 year old again.

[The Awesome Berbaslug!!!]

I imagine this is only slightly more likely to actually happen than the Mars One flight.



Yes, "expected" in 2023, when the rocket being used hasn't managed not to catch fire/explode yet in tests, let alone, you know, reach lunar orbit.

Nah, it's attached to something with too many artemis contracts for it not to happen eventually and this lad has already paid a big chunk of cash, two things which fundamentally separate it from Mars one.

That said the path to this happening is
1. Get to orbit for the first time.
2. Get to orbit enough times that they figure out how to return the booster to the launch pad and catch it,
3. get the ship back from orbit,
4 land it safely
5. Get good enough at all that to start to figure out how to refuel in orbit
6 master that
7. Send it out to the moon to see If the Heatshield can handle the spicy re entry from the moon,
8. Put people on it.
9 don't kill them
10 dear moon.

2023 seems entirely reasonable

[Rogin the Armchair fan]

Can't they test it on Eamonn Holmes first?

[Ginger Yellow]

I imagine this is only slightly more likely to actually happen than the Mars One flight.

The trip is expected to launch in 2023 and take seven days in total.

Yes, "expected" in 2023, when the rocket being used hasn't managed not to catch fire/explode yet in tests, let alone, you know, reach lunar orbit.

[Discordant Resonance]

We'll never hear the end of it!

https://twitter.com/irishexaminer/status/1601155077674504194

[Rogin the Armchair fan]

Probably the coolest thing I've seen this year.

[ursus arctos]

https://twitter.com/KianSharifi/status/1582760645967347717?t=q5nITE1yDzxHbz03oWU3eA&s=19

[The Awesome Berbaslug!!!]

This big hurricane in florida has put the caip bhais/kibbosh on the latest attempt to launch the SLS. The next slot they're looking at is apparently around thanksgiving.