Astrophysics-for-People-in-a-Hurry-8freebooks.net_.pdf
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π°Astrophysics for People in a
Hurry by Neil deGrasse Tysonπ°
For more Stay tuned:- @Astronomy_Learning
Hurry by Neil deGrasse Tysonπ°
For more Stay tuned:- @Astronomy_Learning
What would happen if there were no Moon?
The most immediate effect (other than the lack of moonlight, of course) would be on the Earthβs tides. With only the Sunβs gravitational influence, the difference between high and low tides would be reduced dramatically β as would tidal drag, which slows the Earth down at a rate adding about 0.002 seconds to the length of a day each century. Long term, the effects would be far more serious.
The climate of the Earth is sensitively dependent on the 23.5Β° tilt of the Earthβs axis, and without the stabilising presence of our relatively huge Moon, the gravity of the other planets would produce big changes in this angle β as it does with Mars, whose tilt changes by 60Β° over a few million years.
The most immediate effect (other than the lack of moonlight, of course) would be on the Earthβs tides. With only the Sunβs gravitational influence, the difference between high and low tides would be reduced dramatically β as would tidal drag, which slows the Earth down at a rate adding about 0.002 seconds to the length of a day each century. Long term, the effects would be far more serious.
The climate of the Earth is sensitively dependent on the 23.5Β° tilt of the Earthβs axis, and without the stabilising presence of our relatively huge Moon, the gravity of the other planets would produce big changes in this angle β as it does with Mars, whose tilt changes by 60Β° over a few million years.
πππQUIZ RESCHEDULEDπππ
π° Topic:- Mental Ability Test (MAT)
π’ No. of questions:- 15
β³ Time per question:- 45 seconds
π Date:- 23/08/2021 (Monday)
π Time:- 06:00 PM (IST)
π€΅Taken by:- Vignesh Parkar
If you haven't joined the Discussion Group then join to participate in that.
Link:- @Astronomy_Discussion_Group
Note:- Top 3 Rankers will get a Certificate
Stay tuned:- @Astronomy_Learning
π° Topic:- Mental Ability Test (MAT)
π’ No. of questions:- 15
β³ Time per question:- 45 seconds
π Date:- 23/08/2021 (Monday)
π Time:- 06:00 PM (IST)
π€΅Taken by:- Vignesh Parkar
If you haven't joined the Discussion Group then join to participate in that.
Link:- @Astronomy_Discussion_Group
Note:- Top 3 Rankers will get a Certificate
Stay tuned:- @Astronomy_Learning
How massive can a normal star be?
Estimates made from distance, brightness and standard solar models had given one star in the open cluster Pismis 24 over 200 times the mass of our Sun, making it one of the most massive stars known. This star is the brightest object located just above the gas front in the featured image. Close inspection of images taken with the Hubble Space Telescope, however, have shown that Pismis 24-1 derives its brilliant luminosity not from a single star but from three at least. Component stars would still remain near 100 solar masses, making them among the more massive stars currently on record.
Estimates made from distance, brightness and standard solar models had given one star in the open cluster Pismis 24 over 200 times the mass of our Sun, making it one of the most massive stars known. This star is the brightest object located just above the gas front in the featured image. Close inspection of images taken with the Hubble Space Telescope, however, have shown that Pismis 24-1 derives its brilliant luminosity not from a single star but from three at least. Component stars would still remain near 100 solar masses, making them among the more massive stars currently on record.
Astronomy Learning
πππQUIZ RESCHEDULEDπππ π° Topic:- Mental Ability Test (MAT) π’ No. of questions:- 15 β³ Time per question:- 45 seconds π Date:- 23/08/2021 (Monday) π Time:- 06:00 PM (IST) π€΅Taken by:- Vignesh Parkar If you haven't joined the Discussion Group then join to participateβ¦
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Why don't we receive light from all the stars in the universe?
There are about 6000 stars that are clearly visible to the naked eye above Earth. Yet we know that there are millions of stars in the universe. Since all stars are putting out light and other kinds of electromagnetic radiation and since light can travel for huge distances in space, why can't we see all the stars?
All stars, like our Sun, send out a huge amount of electromagnetic radiation, including light. However, that light spreads out with distance, making it so that only a tiny fraction reaches us. In addition, depending on the temperature of the star, the main color of light sent out by the star changes. Cooler stars put out redder light, hotter stars put out blue or white light. Generally, colors like white or blue are stronger colors (shorter wavelength, higher frequency) and can be seen more easily at far distances than reds, oranges or yellows. Also, some stars are simply larger than others and send out more light.
There are about 6000 stars that are clearly visible to the naked eye above Earth. Yet we know that there are millions of stars in the universe. Since all stars are putting out light and other kinds of electromagnetic radiation and since light can travel for huge distances in space, why can't we see all the stars?
All stars, like our Sun, send out a huge amount of electromagnetic radiation, including light. However, that light spreads out with distance, making it so that only a tiny fraction reaches us. In addition, depending on the temperature of the star, the main color of light sent out by the star changes. Cooler stars put out redder light, hotter stars put out blue or white light. Generally, colors like white or blue are stronger colors (shorter wavelength, higher frequency) and can be seen more easily at far distances than reds, oranges or yellows. Also, some stars are simply larger than others and send out more light.
How were those first stars formed?
Nebulas formed after the Big Bang are vastly known as the home of stars. The gas and dust present inside them were in normal state till any object from the outside created any disturbance. Any object from space that passed near the Nebula or hit that, started movement inside it. These huge movements which were caused by the gravitational force bended the space-time and the gas and dust inside it started to be attracted at a single point. They were attracted till they make up a huge mass like that of Sun or even 100 times bigger than it. This process took millions of years itself. Since it was gaining energy it's temperature kept rising and it became a Pre-stellar core. When the temperature is 1000Β°k the process of Hydrogen fusion started. And thereafter the Pre-stellar core evolved into a Star.
Nebulas formed after the Big Bang are vastly known as the home of stars. The gas and dust present inside them were in normal state till any object from the outside created any disturbance. Any object from space that passed near the Nebula or hit that, started movement inside it. These huge movements which were caused by the gravitational force bended the space-time and the gas and dust inside it started to be attracted at a single point. They were attracted till they make up a huge mass like that of Sun or even 100 times bigger than it. This process took millions of years itself. Since it was gaining energy it's temperature kept rising and it became a Pre-stellar core. When the temperature is 1000Β°k the process of Hydrogen fusion started. And thereafter the Pre-stellar core evolved into a Star.
How far we have explored space and how far can we go?
141 AU which is equal to 141 times of the distance between Earth and Sun, Voyager 1 is able to travel the most in history. Even after travelling at the speed of 17 km/sec in space, which may sound a lot, it will take 1,700,000,000 years for Voyager 1 to cross the Milky Way Galaxy. Proxima Centauri, the second closest star from Earth after Sun is 4.2465 light year away and it would took 40,000 years for Voyager 1 to reach it. Parker Solar Probe recorded the highest speed in space which is 692,000 km/h and still it would take more than 50,000 years to reach destinations like Proxima Centauri. Now if we need to explore exoplanets, the factor we need to devolop is speed. Out of many ways, most well known way to travel faster in space is Warp Drive where we use Antimatter to gain speed. Antiatoms are successfully built and research over Antimatter are being done. Big Bang should have produced huge amount of Antimatter which may be lying far away in Universe.
141 AU which is equal to 141 times of the distance between Earth and Sun, Voyager 1 is able to travel the most in history. Even after travelling at the speed of 17 km/sec in space, which may sound a lot, it will take 1,700,000,000 years for Voyager 1 to cross the Milky Way Galaxy. Proxima Centauri, the second closest star from Earth after Sun is 4.2465 light year away and it would took 40,000 years for Voyager 1 to reach it. Parker Solar Probe recorded the highest speed in space which is 692,000 km/h and still it would take more than 50,000 years to reach destinations like Proxima Centauri. Now if we need to explore exoplanets, the factor we need to devolop is speed. Out of many ways, most well known way to travel faster in space is Warp Drive where we use Antimatter to gain speed. Antiatoms are successfully built and research over Antimatter are being done. Big Bang should have produced huge amount of Antimatter which may be lying far away in Universe.
π°Astronomy Events (September 2021)π°
September 1:- Aurigid Meteor Shower
September 7:- New Moon
September 14:- Neptune at Opposition
September 14:- Mercury at Greatest Eastern Elonganation
September 20:- Full Moon (Harvest Moon)
September 20:- Mars at Apogee
September 22:- September Equinox
September 1:- Aurigid Meteor Shower
September 7:- New Moon
September 14:- Neptune at Opposition
September 14:- Mercury at Greatest Eastern Elonganation
September 20:- Full Moon (Harvest Moon)
September 20:- Mars at Apogee
September 22:- September Equinox
π°Astronomy Events (October 2021)π°
October 2:- Andromeda at Cultimation
October 6:- New Moon
October 7-8:- Draconids Meteor Shower
October 8:- Mars at Solar Conjuction
October 20:- Full Moon (Blood Moon)
October 21-22:- Orionids Meteor Shower
October 25:- Mercury at Greatest Western Elonganation
October 29:- Venust at Greatest Eastern Elonganation
October 2:- Andromeda at Cultimation
October 6:- New Moon
October 7-8:- Draconids Meteor Shower
October 8:- Mars at Solar Conjuction
October 20:- Full Moon (Blood Moon)
October 21-22:- Orionids Meteor Shower
October 25:- Mercury at Greatest Western Elonganation
October 29:- Venust at Greatest Eastern Elonganation
π°Astronomy Events (November 2021)π°
November 4:- New Moon
November 4-5:- Taurids Meteor Shower
November 5:- Uranus at Opposition
November 8:- Lunar Occultation of Venus
November 12:- Northern Taurids Meteor Shower
November 17-18:- Leonids Meteor Shower
November 19:- Full Moon (Frost Moon)
November 19:- Partial Lunar Eclipse
November 4:- New Moon
November 4-5:- Taurids Meteor Shower
November 5:- Uranus at Opposition
November 8:- Lunar Occultation of Venus
November 12:- Northern Taurids Meteor Shower
November 17-18:- Leonids Meteor Shower
November 19:- Full Moon (Frost Moon)
November 19:- Partial Lunar Eclipse
π°Astronomy Events (December 2021)π°
December 2:- Winter Solstice
December 4:- New Moon
December 4:- Total Lunar Eclipse
December 7:- Venus at its brightest
December 13-14:- Geminids Meteor Shower
December 16:- Coma Berenicid Meteor Shower
December 19:- Full Moon (Cold Moon)
December 21-22:- Ursids Meteor Shower
December 2:- Winter Solstice
December 4:- New Moon
December 4:- Total Lunar Eclipse
December 7:- Venus at its brightest
December 13-14:- Geminids Meteor Shower
December 16:- Coma Berenicid Meteor Shower
December 19:- Full Moon (Cold Moon)
December 21-22:- Ursids Meteor Shower