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Fortunately, we now have space telescopes monitoring the Sun from all angles, so we know if there are sunspots forming on the opposite side of the Sun. Moreover, sound waves travel slightly faster in regions of high magnetic field, and waves generated in active regions traverse the Sun about 6 seconds faster than waves generated in quiet regions. By detecting this subtle difference, scientists can provide warnings of a week or more to operators of electric utilities and satellites about when a potentially dangerous active region might rotate into view. With this warning, it is possible to plan for disruptions, put key instruments into safe mode, or reschedule spacewalks in order to protect astronauts.

Solar neutrinos

The second technique for obtaining information about the Sun’s interior involves the detection of a few of those elusive neutrinos created during nuclear fusion. Recall from our earlier discussion that neutrinos created in the center of the Sun make their way directly out of the Sun and travel to Earth at nearly the speed of light. As far as neutrinos are concerned, the Sun is transparent.

About 3% of the total energy generated by nuclear fusion in the Sun is carried away by neutrinos. So many protons react and form neutrinos inside the Sun’s core that, scientists calculate, 35 million billion (3.5 × 10 16 ) solar neutrino s pass through each square meter of Earth’s surface every second. If we can devise a way to detect even a few of these solar neutrinos, then we can obtain information directly about what is going on in the center of the Sun. Unfortunately for those trying to “catch” some neutrinos, Earth and everything on it are also nearly transparent to passing neutrinos, just like the Sun.

On very, very rare occasions, however, one of the billions and billions of solar neutrinos will interact with another atom. The first successful detection of solar neutrinos made use of cleaning fluid (C 2 Cl 4 ), which is the least expensive way to get a lot of chlorine atoms together. The nucleus of a chlorine (Cl) atom in the cleaning fluid can be turned into a radioactive argon nucleus by an interaction with a neutrino    . Because the argon is radioactive, its presence can be detected. However, since the interaction of a neutrino with chlorine happens so rarely, a huge amount of chlorine is needed.

Raymond Davis , Jr. ( [link] ) and his colleagues at Brookhaven National Laboratory , placed a tank containing nearly 400,000 liters of cleaning fluid 1.5 kilometers beneath Earth’s surface in a gold mine at Lead, South Dakota. A mine was chosen so that the surrounding material of Earth would keep cosmic rays (high-energy particles from space) from reaching the cleaning fluid and creating false signals. (Cosmic-ray particles are stopped by thick layers of Earth, but neutrinos find them of no significance.) Calculations show that solar neutrinos should produce about one atom of radioactive argon in the tank each day.

Davis experiment.

Left: photograph of Raymond Davis. Right: photograph of Davis’ neutrino detection experiment in a gold mine in South Dakota. A portion of the tank is seen with an access walkway on top of the tank.
(a) Raymond Davis received the Nobel Prize in physics in 2002. (b) Davis’ experiment at the bottom of an abandoned gold mine first revealed problems with our understanding of neutrinos. (credit a: modification of work by Brookhaven National Laboratory; credit b: modification of work by the United States Department of Energy)

Questions & Answers

why people go to other planet
Rehan Reply
to explore mysteries and also for some new resources and life form
YOG
Presumably to find an alternative for our earth, since our population has been increasing at a crazy rate and we'd slowly be running out of space here, if we'd continue. Another point would be the scientific value. Apart from testing our knowledge we always hope to find a new form of life.
creative
and in future when life from earth will vanished then to maintain our existance we need a new planet.
YOG
History shows our insatiable appetite for energy. The mass tends to congregate around developed communities where energy is readily accessible. It's inevitable we will be become exo-tellurians. Necessity fuels our explorations.
Jocofranc
👏 Well said! @jocofranc knight
Jennifer
what was before big bang
Manish Reply
The creator and their empire
Mahesh
Like ur answer but submitting a light-hearted suggestion of my own : Our universe a galactic-verse of many other billions that are clustered tightly together in a super-constellate. The Big Bang was the result of a magnetic wave originating from inside the constellate desrupting our serene corner.
Jocofranc
nice to here jocofranc, please explain what is before big bang
Mahesh
This increasingly hypothetical scenario suggest that the Big Bang was created when a superwave from this so-call Super-Constellate destabilized our dormant singularity. The wave was the catalyst. When this wave stops buckling our galactic-verse, it will recede back to a singularity. Ok it was God.
Jocofranc
how fast light travel around the earth
Starbuck Reply
lol
Videos
how was moon formed
Kosi Reply
what is steral evolution (star evolution
meron Reply
hi
Nisha
when a star's mass changes over time
Joe
hi
Joe
hi
Lisette
Hii
Asim
hi
Nisha
what big bang
Nisha
yes joe over time chang star mass
Nisha
star prouduce nucluer fusion first stag ( hydroge fusion helium- carbon-neon-oxygen-silicon- last fusion iron hevy star mass not handle iron blast super nova
Nisha
what is the worm hole theory
Nisha Reply
it states that you can travel back through time by this. It's like folding a paper into half and making two points, and there states that you can bend spacetime but according to Einstein's equation that it can break easily and only really small particles can pass through it.
Dark
dark dream what is dark matter
Nisha
what is the great filter theory
Nisha
the great filter theory it's just like the literally filtering it says that when once a civilization achieved its highest state or let's say the highest technology for instance their civilization will end.
Dark
what is radio burst
Nisha
please answer
Nisha
what is the simulatin hypothies
Nisha
smart obsevatin
Nisha
In radio astronomy, a fast radio burst (FRB) is a transient radiopulse of length ranging from a fraction of a millisecond to a few milliseconds, caused by some high-energy astrophysical process not yet identified. We can say that this can be they way to at least know if there's other civilizations~
Dark
~out there
Dark
Simulation hypothesis it proposes that the earth, the universe and the reality you are in is just an artificial simulation or like you are living in a computer simulation.
Dark
sir possible time travel
Nisha
?
Nisha
Yes. Everything is possible.
Dark
replay
Nisha
thanks
Nisha
sir how to make neutron star
Nisha
replay
Nisha
?
Nisha
sir what is the white hole?
Nisha
hi good morning
Nisha
why does the matter of an objects density change the fabric of space time rather than the objects volume..? (hopefully I have expressed that question properly) thanks
Daijahrel Reply
because an objects density consists of it's energy & momentum. an objects volume, for example a photon can have no density (hopefully I expressed that answer properly)
Joe
I suppose each Individual has his or hers different laws and assumptions, so it can be difficult to ask and answer physics questions, but discussions are always positive
Joe
how
Melaku
which matter use rocket
Nisha
Does their is any procedure of star making
Asim Reply
Hope That Helps.....
Adam
how to produce star and how to dead star?
Nisha
waad mahad santnihiin dhamaan waxaan doonayaa inaan wax ka barto astronomyga waa maxay xidigis?
Abdicaroog Reply
understanding astronomy
ricardo Reply
What About Understanding Astronomy?
Adam
yap
Janmarc
what is astronomy?
Janmarc
define..
Janmarc
Currently, I'm studying in 10th grade. What should I do after my 10th so that I can get an astronomy career?
Chaya Reply
try jee exam and achieve a good score in jee advance to join in IIST(Space research institute)
Sri
okay.. thanks
Chaya
Hey there I want to be an astrophysicist... and I'm grade 9... what should I do to be an astrophysicist
Aymen
Know more about space,watch movies related to space ,and to become an astrophysicist u should be very good in physics,train urself to think everything logically. Start to focus on JEE Exam ,train urself or join any institute which is good in coaching for JEE ,then if u score high ,u can join IIST
Sri
Which is the best university for Astronomy
Asim
Probably Massachusetts Institute Of Technology.....
Adam
Math Math Math, Get Familiar With All Types Of Math.....
Adam
Which subject is most important for Astronomy
Asim
Geometry, Algebra, Calculus, Trigonometry, Do Alot Of It And Often.....
Adam
I Can't Say It Enough, Math Is The Language Of The Cosmos.....
Adam
Adam you are in which university?
Asim
I Went To University But Never Finished My Degree..... Had To Work And Couldn't Afford School.....
Adam
MaryMount University..... Philosophy Of Science Major.....
Adam
It ia a cathloic University. Am i write
Asim
And its main campas is in Arlington country
Asim
No, It's In New York City.....
Adam
It's Not A Catholic University.....
Adam
Ohh sorry
Asim
Are you interested in Astronomy
Asim
IIT ain't so good for Pure Astronomy. If you want to know how the universe works,go for pure science. If you want to make spacecraft,go for Aerospace Engineering
priyanshu
Your are in which university brother
Asim
I Love Astronomy, I'm An Active Amateur Astronomer.....
Adam
I also love Astronomy very much
Asim
And to help me to solve some puzzling questions
Asim
this famous person was the first to recognise earthshine on the moin
Rajan Reply
Leonardo Da Vinci.....
Adam
what is string theory?
sakshi Reply
A Cosmological Theory Based On The Exsistence Of Cosmic Vibrating Strings.....
Adam
Good Morning Asim Ali.....
Adam
I Can't Do That, You Can Ask Me What Ever You Want.....
Adam
If you don't mind can i ask why?
Asim
Do You Understand The Millions Of People Have Access To This Site, I Wouldn't Put My Information Out There, Knowing What People With Bad Intent Can Do With Personal Information.....
Adam
Ohh sorry
Asim
My question is that, there are many collision of stars in a day So that cause black hole. But is there any procedure of star making? Hopefully i ask my question properly.
Asim
No Need To Apologize, I Will Answer Anything You Need Answered And If I Can't Answer It I Will Guide You To The Answer.....
Adam
Thier Is Only One Way Stars Are Made, Gravity Makes Matter Come Together, And When The Amount Of Matter Gets Massive Enough Nuclear Fusion Starts Up And A Star Is Born.....
Adam
What is white drawft?
Asim
A White Dwarf Is A Low Mass Star That Has Exhausted All It's Central Nuclear Fuel And Lost It's Outer Layers As A Planetary Nebula.....
Adam
what is the great filter theory
Nisha
hi adam what is great filter theory
Nisha
Well First It's Not A Theory, It's A Hypothesis, The Great Filter Hypothesis States That What Ever Causes Dead Matter To Under Go Abiogenesis(Start Of Life) Must Be Very Hard And Very Rare In Our Universe, Because So Far We Only See 1 Civilisation That Made Through All The Requirements For.....
Adam
Intelligent Life, So Far Only Our Planet Has Intelligent Life, That We Know Of, And Again This Is Only A Hypothesis, No Evidence Exist To Back This Up.....
Adam
hi adam sir
Nisha
Good Day.....
Adam
Good to see you sir
Asim
hi
Nisha
good day
Nisha
hi
Nisha
Same Here.....
Adam
What's The Good Word For The Day?
Adam
Does MIT have good astrophysics courses ?
priyanshu Reply
Probably The Best In The United States.....
Adam
But Don't Get Caught Up On Who's The Best, You Can Be The Next Noble Winning Astrophysicist.....
Adam
hmmm..........that's nice one....Adam had said.....
Gospel
How did ASTRONOMY helped you understand yourself ? 🤔
Hussain Reply
ln Soo many ways .it helped me to know my abilities ND understanding my goals
Kosi
helped in understanding the limitless thinking ability of human brain 😉
Mahesh
@mahesh babu @kosi Nightingale agree!!! We are all part of the universe 💯
Jennifer
😀 nice to here from you.. @kosi @jennifer thomas
Mahesh
@mahesh babu @kosi Nightingale Sorry about ? it was a mistake lol nice to meet you guys as well. Great question! Enjoy this amazing day guys!
Jennifer
lol
Mahesh
It helped me know what I want to work toward
Karolein

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Source:  OpenStax, Astronomy. OpenStax CNX. Apr 12, 2017 Download for free at http://cnx.org/content/col11992/1.13
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