How much is known about Neptune's atmosphere, more precisely about "raining diamonds"?
The atmosphere of Neptune is, in many ways, similar to that of Uranus. However, its dynamics are presented in a complex configuration of strong winds that sweep the planet, besides the formation of cyclonic storms and clouds, with clearly visible visual characteristics.
The upper atmosphere of Neptune is made up of 79% hydrogen, about 18% helium and most of the remaining methane, the presence of which imparts the blue-indigo color of the planet by absorbing the incident red radiation.
The diamond rain on Neptune and Uranus was predicted long ago, because of the pressure inside the planet that could be formed by carbon and hydrogen. But now it was virtually confirmed by an experiment conducted by an international team of scientists, this “diamond rain” was recreated under laboratory conditions for the first time, giving us the first glimpse into what things could be like inside ice giants.
At about 10,000 km below the surface of these planets, hydrocarbon compression is thought to create diamonds. To recreate these conditions, the international team submitted a polystyrene plastic sample to two shock waves using an intense optical laser in the Matter in Extreme Conditions (MEC) instrument, which were then paired with X-ray pulses from Linac Coherent Light Source SLAC (LCLS).
Polystyrene is made from a mixture of hydrogen and carbon, key components of the general chemical composition of the ice giants. In the experiment, the team was able to see that almost all of the carbon atoms in polystyrene were embedded in small diamond structures up to a few nanometers wide.
However, in Uranus and Neptune, scientists predict that diamonds would become much larger, perhaps millions of carats by weight.
2°image: (This false color photograph of Neptune was made from Voyager 2 images taken through three filters: blue, green, and a filter that passes light at a wavelength that is absorbed by methane gas. Thus, regions that appear white or bright red are those that reflect sunlight before it passes through a large quantity of methane). 1°image, 3°image & 4°image.
Here are two links if you want to read about it: Click here and here.
Scenes from Apollo 16 mission to the Moon, April 1971: Pre-landing pics of earthrise, with the command module visible just above the lunar horizon to the left of Earth.
“As we look farther back in time, we find that younger galaxies formed stars at faster rates than galaxies do today. We can measure the star-formation rate, and find that at earlier and earlier times, it was more intense. But then we find it hits a peak when the Universe is about two billion years old. Go younger than that, and the rate goes down again.”
We’ve come incredibly far in our quest to learn how the Universe came to be the way it is today. We can see out in space for tens of billions of light years, to galaxies as they were when the Universe was only a few percent of its present age. We can see how galaxies evolve, merge and the stars inside change. And we can see to even before that, when no stars or galaxies existed at all. But how did we get from there to here? There are still plenty of gaps in the story. We’ve never seen the first stars or galaxies; we’ve never witnessed the start of cosmic reionization; we’ve never seen the star formation rate jump from zero to a real, finite number. Yet with James Webb and WFIRST on the horizon, these gaps in our knowledge may – if we’re lucky – all disappear.
Come get the story on what we know about the first galaxies, and what we hope and have left to still learn!
In October 2017, astronomers announced the first detection of gravitational waves from the merger of two neutron stars earlier that year. The event also rung in the era of multi-messenger astronomy, as more than 70 telescopes observed the event’s afterglow in optical light, X-rays, gamma rays, and more. Now, an X-ray signal dubbed XT2 from a galaxy 6.6 billion light-years away has revealed another neutron star merger, which left behind a single, heavier neutron star with an incredibly powerful magnetic field: a magnetar.
Read more ~ astronomy.com
Image: Chandra observations show the flare-up and subsequent dimming of XT2, which matches predictions for the signal from a pair of merging neutron stars and the birth of a magnetar. Credit: X-ray: NASA/CXC/Uni. of Science and Technology of China/Y. Xue et al; Optical: NASA/STScI
Okay so I just finished my first semester in university and lets just say I’ve got to change my whole learning/studying style to be able to survive here. Here are some of the things I’ve learnt to do and will be doing in second semester:
1. Start backwards:
I highschool, you try to learn the subject by going to class, listening to the teacher, then going home, reading the textbook, then doing the homework, then making notes, then studying for the final. In engineering, you have to do this backwards: You will realize that you are going to be basically teaching yourself the content one way or another soon before the finals, so better start now. First, go through the past exams and past papers - make a list of all the major topics covered (example: if in an electrical circuits course, a question on a past final exam is “find the equivalent circuit using thevenin’s theorem” then write Thevenin’s theorem as a topic to be learned). Then go on youtube and find videos that explain each of these topics to you and make rough notes on these topics. (Reblog if you want me to make a master list of all the youtubers that teach engineering really well). Then go through he textbook and find sample questions not he theorem/topic you learnt off of youtube, and solve them. Then write your doubts in a notebook. Then go to class and have two notebooks open : one where you are taking notes of what the prof is saying, and one which has your practice problems solved, and see if the prof clarifies your doubts in the lecture. The lecture should be review of what you learnt at home!!!! Then, after class go to the prof and clarify any doubts. Then go home and make final notes on the topic. I like to make notes on cue cards (more on this later). Then go back to the final exam and see if you can solve the problem.
2. Make cue cards:
I like to get index cards and write a short note on how to solve each type of question I am likely to see on a final exam on each question card. Example: one cue card for “how to find resistance using wheatstone bridge” . I link the cue cards with a clip and its easier to carry the around and study.
3. Get pretty notebooks and organize your stationary. Its easier to stay focused when everything is pretty.