Intermediate-mass black holes (IMBHs) are a long-sought ‘missing link’ in black hole evolution. Only a few other IMBH candidates have been found to date. Most known black holes are either extremely massive, like the supermassive black holes that lie at the cores of large galaxies, or relatively lightweight, with a mass less than 100 times that of the Sun. Black holes are one of the most extreme environments humans are aware of, and so they are a testing ground for the laws of physics and our understanding of how the Universe works. If IMBHs exist, how common are they? Does a supermassive black hole grow from an IMBH? How do IMBHs themselves form? Are dense star clusters their favoured home?
If the distribution of those nine satellite galaxies across the entire Milky Way is similar to what was found in the footprint captured by the HSC-SSP, the research team calculates that there actually may be closer to 500 satellite galaxies
WTF? I was thinking there were around a dozen or so.
Higher speed impacts penetrate deep, but also cause the rock to melt. This fills in deeper craters, limiting the max depth a crater can be. There are still very deep huge craters, but these look more like big depressions than craters, because of how big they are. They are also themselves covered with craters usually, making their size and shape harder to see.
Because the diameter of the moon is 3474km, a difference of several kilometers would only amount to a fraction of a percent. So even though one crater is for example 10km deeper than another, relative to the size of the moon this is practically nothing. When viewing pics like these where the whole moon is visible, this matters.
The moon is a very uniform gray color and lacks the indicators our brain use to gauge depth. This makes it very hard to guess how deep the different craters are. You can see some craters have more shadows where others don’t, but they are also different shapes and sizes and the lighting is different so it’s hard to see.
There is also probably some part of the speeds of incoming stuff being within a certain range and the moonrocks being relatively uniform in materials, so the range of craters than can exists is probably limited. But I’m not certain how big of an factor this is and what the range is.
There are plenty of missions right now. China has landed a rover on the moon this month. And multiple countries have satellites in orbit around the moon. Nasa has their Lunar Reconnaissance Orbiter which takes very high resolution images of the moon all the time and these are publiced on their website.
This image does a good job at making me realize we have explored basically nothing on the moon. SO much more to explore, yet we act like there’s no point trying to send more astronauts to the moon for decades. Please, increase NASA budget more.
According to the European scientists, “Euclid peered deep into this nursery using its infrared camera, exposing hidden regions of star formation for the first time, mapping its complex filaments of gas and dust in unprecedented detail, and uncovering newly formed stars and planets. Euclid’s instruments can detect objects just a few times the mass of Jupiter, and its infrared ‘eyes’ reveal over 300,000 new objects in this field of view alone.”
What is this website that keeps getting posted here? There is nothing on its site saying who runs it. And this article is almost directly plagiarized from a ScienceNews article: sciencenews.org/…/mars-internet-communication-rov…
“camped” out in Quebec, my son speaks better French than me and has corrected me all weekend, but we’ll see whose in charge when I poke him in the eyes two seconds before totality… Or squeal like a school girl as it approaches, we’ll see which happens!
Noticing a bit of misinformation here so let’s clear this up: take off your eye protection during totality. The corona is so faint you won’t see anything at all through eclipse glasses.
A minor accident had forced me down in the Rio de Oro region, in Spanish Africa. Landing on one of those table-lands of the Sahara which fall away steeply at the sides, I found myself on the flat top of the frustum of a cone, an isolated vestige of a plateau that had crumbled round the edges. In this part of the Sahara such truncated cones are visible from the air every hundred miles or so, their smooth surfaces always at about the same altitude above the desert and their geologic substance always identical. The surface sand is composed of minute and distinct shells; but progressively as you dig along a vertical section, the shells become more fragmentary, tend to cohere, and at the base of the cone form a pure calcareous deposit.
Without question, I was the first human being ever to wander over this . . . this iceberg: its sides were remarkably steep, no Arab could have climbed them, and no European had as yet ventured into this wild region.
I was thrilled by the virginity of a soil which no step of man or beast had sullied. I lingered there, startled by this silence that never had been broken. The first star began to shine, and I said to myself that this pure surface had lain here thousands of years in sight only of the stars.
But suddenly my musings on this white sheet and these shining stars were endowed with a singular significance. I had kicked against a hard, black stone, the size of a man's fist, a sort of moulded rock of lava incredibly present on the surface of a bed of shells a thousand feet deep. A sheet spread beneath an apple-tree can receive only apples; a sheet spread beneath the stars can receive only star-dust. Never had a stone fallen from the skies made known its origin so unmistakably.
And very naturally, raising my eyes, I said to myself that from the height of this celestial apple-tree there must have dropped other fruits, and that I should find them exactly where they fell, since never from the beginning of time had anything been present to displace them.
Excited by my adventure, I picked up one and then a second and then a third of these stones, finding them at about the rate of one stone to the acre. And here is where my adventure became magical, for in a striking foreshortening of time that embraced thousands of years, I had become the witness of this miserly rain from the stars. The marvel of marvels was that there on the rounded back of the planet, between this magnetic sheet and those stars, a human consciousness was present in which as in a mirror that rain could be reflected.
Well that is some spectacular prose, I am truly transported to a place where spirituality and science meet at a single point of grand mystery and realization that I have felt a few times in real life, alone in nature at surprising places and odd hours, but Saint-Exupéry has taken this all one further level up the rung.
To a level that my father actually lived, as an airplane pilot in Baja California back when the peninsula didn’t have a paved road, an isolated, remote place as yet mostly untouched by man.
One minor caveat, however:
a sheet spread beneath the stars can receive only star-dust
While I understand such a thoughtful writer was going for a feeling, surely with his talent he could have found a way to include windstorms, all the dust and sands they can sweep horizontally across the lands and over hills. The Rio De Oro region is in northern Morocco, surely it often gets blasted by powerful Saharan winds.
A sheet spread beneath the Moroccan sky most often receives desert-dust.
“Contrary to standard cosmological theories where the accelerated expansion of the universe is attributed to dark energy, our findings indicate that this expansion is due to the weakening forces of nature, not dark energy,” he continued.
astronomy
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