Space technology Current Affairs - 2019
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Scientists have spotted a new view of the dark, contorted centre of a sunspot that is nearly twice the diameter of the Earth.
It was spotted using Atacama Large Millimetre/submillimetre Array (ALMA) antennas located in Atacama Desert of northern Chile. The discovery is an important expansion of range of observations that can be used to probe the physics of our nearest star.
- Using ALMA antennas capabilities, astronomers imaged the millimetre-wavelength light emitted by the Sun’s chromosphere, the region that lies just above the photosphere that forms the visible surface of the Sun.
- They produced the images to study solar activity at longer wavelengths of light that are typically available to solar observatories on Earth.
- Using two of ALMA’s receiver bands at wavelengths of 1.25 millimetres and three millimetres, scientists were able to observe an enormous sunspot.
- The images captured through it help to reveal differences in temperature between parts of the Sun’s chromosphere and also understanding the heating and dynamics of the chromosphere.
Sunspots: They are darker, cooler areas on the surface of the sun in a region called the photosphere (having temperature 5,800 degrees Kelvin). Sunspots can be very large, up to 50,000 kilometers in diameter and have temperatures of about 3,800 degrees K. They are dark in comparison with the brighter and hotter regions of the photosphere surrounding them.
The Indian Space Research Organisation (ISRO) is planning to set a new world record in space history by launching 103 satellites in one go on a single rocket in the first week of February, 2017.
These satellites will be launched on board of ISRO’s workhorse PSLV (C37) from the Satish Dhawan Space Centre in Sriharikota in Andhra Pradesh. The mission will carry three satellites from India and rest from other countries.
How these satellites will be placed in orbit?
- The satellites will be separated from vehicle in different directions, once launch vehicle reaches the orbital condition. The separation angle and time of separation will be different for every satellite.
- The separated satellites will have relative velocity of one metre per second. So after 1,000 seconds distance between satellite and rocket will be 1,000 metres. It will ensure that satellite will not collide with another.
- The first satellite launched will move at relatively faster velocity than the next satellite. Due to different relative velocities, distance between the satellites will increase continuously but the orbit will remain same.
The present record of highest number of satellites launched in a single mission has been 37 by Russia in 2014. NASA has launched 29 satellites in one go in 2013. In June 2016, ISRO had launched 20 satellites in one go.