f1500/23000
Posted on 10/16/2022 2:51:43 PM PDT by BenLurkin
The Japan Aerospace Exploration Agency intends to launch its DESTINY+ mission to the near-Earth asteroid Phaethon in 2024, with the aim of flying by the space rock in 2028, so this "potentially hazardous" asteroid has been studied intensely in the lead-up to the mission.
Researchers recently made one particularly notable discovery about Phaethon: Its spin is speeding up. The asteroid's rotational period is decreasing by 4 milliseconds per year. Even a small change like this could impact the DESTINY+ observations. Knowing the specific spin rate allows the team to more accurately predict the asteroid's orientation during the spacecraft's flyby — in turn, that allows the team to be more specific with their observations.
It's rare for an asteroid's spin to change; Phaethon is just the 11th known asteroid to show a change in its rotational period, and it's the largest of those space rocks, with an average diameter of 3.4 miles (5.4 kilometers).
Using data and observations from 1989 through 2021, Sean Marshall, a planetary scientist at Arecibo Observatory in Puerto Rico, created a model to determine the shape of Phaethon in preparation for the DESTINY+ mission.
"The predictions from the shape model did not match the data," Marshall said in a statement. "The times when the model was brightest were clearly out of sync with the times when Phaethon was actually observed to be brightest. I realized this could be explained by Phaethon's rotation period changing slightly at some time before the 2021 observations, perhaps from comet-like activity when it was near perihelion [the point in its orbit nearest to the sun] in December 2020."
Marshall determined that the model that best fit the data included constant rotational acceleration — in other words, the regular decrease of Phaethon's rotational period of 4 milliseconds per year.
(Excerpt) Read more at space.com ...
If the rotation is speeding up does that imply that its circumference is shrinking?
An astroid with it’s own name!
A celestial body of influential proportions!
f1500/23000
Its human-imposed name. Who knows what Phaethon calls itself, or whether it even identifies as an asteroid. Maybe it thinks of itself as a dwarf planet. Of course it's a bit small for being a dwarf planet, but it can dream.
and believe me... its 10.... 100 times more appreciated and respected!! your pic isnt crisp and clear but it shows proper perspective and its normal to the mind knowing the picture you took is of something MILLIONS of miles away on a real home telescope and amateur photography!!. it wasnt takin by a probe, then straightened out so the layers are level to the eye and then one moon added with a fake shadow and then say someone took it from a home telescope!! keep em comin!! I’d like to see some of your moon shots!! i get they are detailed enough to boast about!!
BTT!!
get = bet!
Astronomer takes his kid to ballet class. “Your pirouette was fine, but you’re about a millisecond fast. Try to slow it down.”
> I bet if a 3.4 mile diameter asteroid hit Washington D.C., the impact would be heard in Denver...Chandeliers rocking in Las Vegas.
And the cheering would be heard around the world.
Or it could mean that King Ghidorah is waking up again.
“You upset Pele by being on top of Mauna Kea”
I don’t think so, she is pretty quiet on Mauna Kea, but still active.
Kiluea, she is busy, and I expect Mauna Loa will off in my lifetime.
I assisted in engineering studies to verify TMT. I’ve been briefed on it’s design reviews. I think space telescopes are a better bet, if you are going to spend all that money. Mauna Kea is a very harsh place to operate extreme precision optics and instruments. Trying to keep starlight on a few 13 Micrometer Pixels, in 60 KPH winds, with a 30 meter mirror, for an hour will be a challenge.
Better to spend the money curing some Cancer.
I went up to the top, it was cool being above the clouds.
Also the place at certain times of the year, you can see the Southern Cross and still be in America.
Around June 21st?
The only thing to worry about is any changes in the predicted/observed trajectories through our solar system...
We’ll be waiting for the “bend over and kiss your butt goodby” order from the WH...
3200 Phaethon is the progenitor of the Geminid Meteor shower.
Probably closer to a comet than an asteroid, Phaethon may simply be outgassing, which would cause a change in rotational speed.
> The asteroid’s rotational period is decreasing by 4 milliseconds per year.
it’s slowing down, implying some kind of angular de-acceleration or increasing in diameter. Or both.
you’d think if they could tell you how many milli-radians per year it was slowing down they could tell you how much energy it would take. The radar image showed it was slightly asymmetric about the axis of rotation. Maybe the lobe outgasses a bit around aphelion...or maybe the rubble pile is expanding?
ha, 3.7×10-8 rad/day squared, so it’s way less than milli-radians. Like 37 nano-radians per day squared.
> I think space telescopes are a better bet, if you are going to spend all that money.
5 bucks says at the time the risk assessment and value per dollar were assessed, it wasn’t a very sure bet. But someday soon.
I kinda wonder why Arecibo hasn’t been replaced by giant phased arrays in some remote locations. Though space based phased array radio-telescopes would be groovy too.
asteroids don't concern me farmguy
That is an amazingly good question.
I paid Elon $500 for a consumer-grade phased array antenna that can track multiple satellites in LEO. I bet the amount of money a major observatory could raise would buy a gonzo phased array setup.
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