What is the Stratospheric
Observatory for Infrared Astronomy, or SOFIA, up to?
SOFIA, the
Stratospheric Observatory for Infrared Astronomy, as our flying telescope is called, is a Boeing 747SP aircraft
that carries a 2.5-meter telescope to altitudes as high as 45,000 feet.
Researchers use SOFIA to study the solar system and beyond using infrared
light. This type of light does not reach the ground, but does reach the
altitudes where SOFIA flies.
Recently, we used SOFIA to study water on Venus, hoping to
learn more about how
that planet lost its oceans. Our researchers used a powerful instrument on
SOFIA, called a spectrograph,
to detect water in its normal form and “heavy water,” which has an extra
neutron. The heavy water takes longer to evaporate and builds up over time. By
measuring how much heavy water is on Venus’ surface now, our team will be able
to estimate how much water Venus had when the planet formed.
We are also using SOFIA to create a detailed map of the Whirlpool
Galaxy by making multiple observations of the galaxy. This map will help us
understand how stars form from clouds in that galaxy. In particular, it will
help us to know if the spiral arms in the galaxy trigger clouds to collapse
into stars, or if the arms just show up where stars have already formed.
We can also use SOFIA to study methane on Mars. The Curiosity rover
has detected methane
on the surface of Mars. But the total amount of methane on Mars is unknown and
evidence so far indicates that its levels change significantly over time and
location. We are using SOFIA to search for evidence of this gas by mapping the Red
Planet with an instrument specially tuned to sniff out methane.
Next our team will use SOFIA to study Jupiter’s icy moon Europa, searching for evidence of possible water plumes detected by the Hubble Space Telescope. The plumes, illustrated in the artist’s concept above, were previously seen in images as extensions from the edge of the moon. Using SOFIA, we will search for water and determine if the plumes are eruptions of water from the surface. If the plumes are coming from the surface, they may be erupting through cracks in the ice that covers Europa’s oceans. Members of our SOFIA team recently discussed studying Europa on the NASA in Silicon Valley Podcast.
This is the view of Jupiter and its moons taken with SOFIA’s
visible
light guide camera that is used to position the telescope.
Often times you look at really pretty images of Supernova remnants (what is left after a supernova explosion)
and are blown away by their magnificence. But the sad truth is that
there are not a lot of these supernovas that we can observe in such
great detail.
On the
bright side, in general there are lots of supernovas to observe in the
universe. And the above is a spectacular time-lapse of the Supernova SN 2015F illustrating how the Luminosity of a Supernova varies with time.
Last week we were talking about wind patterns and how they affect flight time. But it is also worth mentioning that Space shuttles are launched almost at all times from West to East to take advantage of the earth’s rotation
How does earth’s rotation affect shuttles ?
Earth is a spherical body rotating with some angular velocity. And as a result of this, the equator is rotating at a higher velocity than the poles. By launching a space shuttle from the equator you are getting a ‘speed boost’.
This means that if a shuttle is launched from the pole, it has to accelerate from 0 to 17000mph to reach orbital velocity.
But if a shuttle is launched from the equator, it only needs to accelerate from 1025 to 17000mph. (that 1025mph initial velocity is given by the earth free of charge)
This saves valuable amount of fuel required for propulsion
Polar Orbits
Not all rockets are launched from the west to east and the direction is determined by the purpose of its payload.
The satellites that are used for mapping for instance follow a Polar Orbit i.e they move from north to south or vice versa and therefore during launch they cannot take advantage of the earth’s rotation.
Florida or California
Another characteristic of launching satellites is that the launching
stations are generally located near the coast just in
case of failure of the launch, the satellite falls in an uninhabited area.
NASA primarily uses Kennedy Space Center, Florida for east-west launches and Vandenberg Base California for polar orbits for the very same reason. ***
With all the media frenzy about Spacex over the days we received a few requests asking us to explain how satellites are launched into orbit.
We shall do so through a thought experiment proposed by Isaac Newton when he was trying to understand how the moon was orbiting the earth.
Newton’s cannonball
Just imagine standing on top of a really tall mountain with some cannonballs and a cannon.
We will start firing these cannon balls with different speeds by constantly increasing the amount of firepowder that we add and observing the response.
(a) Speed of cannonball < 7300 m/s
(b) Speed of cannonball ~7300 m/s —-> Circular orbit
( c) Speed of cannonball ~8000 m/s —-> Elliptical orbit
(d) Speed of cannonball ~11200 m/s —-> Parabolic trajectory
(e) Speed of cannonball – Crazy
Gunpowders are not that powerful !
In the real world instead of using gun powder, we use much more sophisticated and powerful
solid rocket fuels which will take the satellite from earth and put it
in orbit.
But once the satellite once put in orbit just keeps falling into orbit.
This applies to the ISS as well: “ISS is always falling; Falling into orbit.”
Although this is not by any means a comprehensive post on this topic, but hopefully this gives you a sense of the physics of how satellites are placed in orbit.
34 years ago, on this day NASA Astronauts performed the first untethered spacewalk. And yesterday Spacex just put a Tesla Roadster in an orbit to Mars. This is truly an exciting time to be alive.
Dyson sphere is a hypothetical mega-structure that completely encompasses a star and captures most or all of its power output.
Over the years many variants have been explored:
The simplest such arrangement is the Dyson ring, in which all ‘energy harvesting structures’ share the same orbit.
Add multiple Dyson ring structures and you will get a Dyson swarm.
Now what if you didn’t like a consistent orbit for your structures, you could employ a solar sail to continuously modify its orbit( called a statite ).
Such an arrangement would be known as a Dyson Bubble
Then there is the fictionally popular version – The Dyson Shell, where a uniform solid shell of matter just encapsulates the entire star.
And many many more. But you get the gist.
Could there be Dyson Spheres out there?
When scientists were monitoring the brightness from some stars, they
found that it fluctuated in some odd ways like so:
Brightness v/s time for KIC 8462852
It is common for such dips to occur since when a planet eclipses a star, there would a drop in the brightness observed from the star.
Brightness v/s time for a binary star system
But what was baffling was the duration and period of occurrence of these dips.
Although the main line of rationale remains as asteroid impact remnants or interstellar collisions causing these aberrations in data.
But to say that these could the signs of an alien civilization does remain to be the more entertaining interpretation.
Last week we were talking about wind patterns and how they affect flight time. But it is also worth mentioning that Space shuttles are launched almost at all times from West to East to take advantage of the earth’s rotation
How does earth’s rotation affect shuttles ?
Earth is a spherical body rotating with some angular velocity. And as a result of this, the equator is rotating at a higher velocity than the poles. By launching a space shuttle from the equator you are getting a ‘speed boost’.
This means that if a shuttle is launched from the pole, it has to accelerate from 0 to 17000mph to reach orbital velocity.
But if a shuttle is launched from the equator, it only needs to accelerate from 1025 to 17000mph. (that 1025mph initial velocity is given by the earth free of charge)
This saves valuable amount of fuel required for propulsion
Polar Orbits
Not all rockets are launched from the west to east and the direction is determined by the purpose of its payload.
The satellites that are used for mapping for instance follow a Polar Orbit i.e they move from north to south or vice versa and therefore during launch they cannot take advantage of the earth’s rotation.
Florida or California
Another characteristic of launching satellites is that the launching
stations are generally located near the coast just in
case of failure of the launch, the satellite falls in an uninhabited area.
NASA primarily uses Kennedy Space Center, Florida for east-west launches and Vandenberg Base California for polar orbits for the very same reason. ***
Summary: Around 1997, there were three great storms named FA, DE and BC on Jupiter. Then DE got jealous that BC was getting all the attention from Earthlings and went on a vortex attack ,destroyed it and ascended the throne as BE.
When FA came to know about what had happened, it summoned all the gases and went on a full out attack on BE to become BA
Ecstasy Shots 