"My wife told me I should get out more. I replied that I am just about to celebrate my 66th free trip around the sun. Can anyone tell me how far I have traveled around the galaxy during that time?"All of the information required to answer this question to a ballpark level of accuracy — along with a little elementary arithmetic — can be found in the Galaxy Song from Monty Python's comedy film The Meaning Of Life.
"We're thirty thousand light-years from galactic central point,So the circumference of the Earth's orbit is (roughly) pi times two times thirty thousand light years. That's approximately 188,495 light years. And we take 200 million years to complete an orbit, which means each year we cover 188,495/200,000,000 light years, which is 0.00094 light years.
We go 'round every two hundred million years..."
"As fast as it can go, the speed of light, you know,Twelve million is actually a bit high. C is precisely 299792458 meters per second¹, which is 186,282.4 miles per second, and that works out to 11,176,943 miles per minute. 186,282.4 miles times 86400 seconds per day times 365.24 days per year gives 5,878,464,425,192.5 miles to the light year. Each year we travel 0.00094 of those around the galaxy, which is 5,525,756,559.7 miles, or just over five and a half trillion miles. Multiply by 66 and you get 364,699,932,939 miles, give or take a few hundred yards.
Twelve million miles a minute, and that's the fastest speed there is"
For many at the Johns Hopkins Applied Physics Laboratory, January 1 this year didn't mean a New Year's celebration. Instead, it meant the first arrival of data from New Horizons' visit to a small Kuiper Belt object. But, like its earlier flyby of Pluto, the probe was instructed to grab all the data it could and deal with getting it back to Earth later. The full set of everything New Horizons captured won't be available for more than a year yet. But with 10 percent of the total cache in hand, researchers decided they had enough to do the first analysis of 2014 MU69.#Astronomy #Space #NewHorizons #Exploration #2014MU69 #UltimaThule #KuiperBeltObjects
Overall, 2014 MU69 looks exactly like what we'd hope for: a world that underwent some major changes immediately after its formation but has since become static, preserving its state largely as it was billions of years ago. Hopefully, more details on that state are sitting in storage on New Horizons. Because we're not likely to send something back to 2014 MU69 any time soon.
After the monumentally successful flyby of Pluto in 2015, the New Horizons spacecraft continued on into the outer solar system. After traveling at more than a dozen kilometers per second out an additional billion kilometers or so, it shot past the odd little rocky iceball 2014 MU69 on January 1, 2019, passing it by the razor-thin margin of just 3,500 kilometers … and that was after traveling for over 6.6 billion kilometers from Earth!#Space #Astronomy #Asteroids #NewHorizons #MU69 #UltimaThule #Exploration
New Horizons took a lot of data during this encounter, comparable to what it did at Pluto, and it'll be another year or more before it's all back on Earth. So the New Horizons team did a clever thing: They prioritized what images to send back first. Among the highest priorities was getting the highest-resolution image sent back from the closest encounter as quickly as possible.
And now that image is here.
You might think that being out there, exposed to space out past Neptune for billions of years, MU69 would be covered in craters. For Pluto that's not the case because we think its surface gets repaved, so to speak, from subsurface processes that bubble up liquid from the interior. However, MU69 is far too small for that, and is certainly solid throughout. So a dearth of craters means there must be a dearth of impactors.
Interestingly, some scientists actually predicted this! They used the number of small craters seen on Pluto and its huge moon Charon, together with measurements and estimates of sizes of small objects past Neptune (called trans-Neptunian objects [TNOs], or more specifically in this case the Kuiper Belt), first to try to figure out the size distribution of objects out there capable of hitting MU69, and then to predict the size distribution of craters on MU69. Keep in mind that this was all done before the MU69 encounter!