There are the Sketches of the four moons of Jupiter (Io, Europa, Ganymede and Callisto), as seen by Galileo
through his telescope.

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                                                 Source

The drawing depicts observations from the time period January 7 to 24, 1610.

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The above is the sequence of photographs taken by JunoCam aboard the Juno
spacecraft, in June 2016, of Jupiter and the motion of the four Galilean
moons, as the spacecraft approached the planet.

* There are 79 known moons of Jupiter.

** Jupiter has 4 rings.

Emojis of the cosmos

Pareidolia  is a psychological phenomenon in which the mind responds to a stimulus, usually an image or a sound, by perceiving a familiar pattern where none exists.

These are merely some images of stars and galaxies taken by the Hubble Space Telescope. But what do you see ?

Astronomy From 45,000 Feet

nasa:

What is the Stratospheric
Observatory for Infrared Astronomy, or SOFIA, up to?

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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.

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 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.

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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.

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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.

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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.

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This is the view of Jupiter and its moons taken with SOFIA’s
visible
light guide camera that is used to position the telescope.  

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com

In addition to conventional means of space observation like from space telescopes(like Hubble)

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and telescopes on the ground (like the Keck Observatory)

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SOFIA (or the flying telescope) is yet another tool that Astronomers use on a regular basis to study our universe.

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Resource: 
Inside NASA’s SOFIA Airborne Astronomical Observatory
 

Why does one image look better ?

Filters are very important in astronomical observation as they reduce glare and light scattering, increase contrast through
selective filtration, increase definition and resolution, reduce
irradiation and lessen eye fatigue.

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                                         Working of a magenta filter

Depending on which object you are looking, one chooses the appropriate filter. For instance the cover photo is without and withthe moon filter.

And on an amateur telescope they is how they are inserted.

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                                        Eye-piece filter (Source)

Telescopes like the Hubble have plenty of these filters stacked on them. You can find a list of the filters here.

Some popular filters commonly used are as follows:

Red –                           R

Green –                        V

Blue –                           B

Infrared –                      i’

Ultraviolet –                  u’

Hydrogen Alpha –       H-alpha

Oxygen III  –               OIII

LPR (Light Pollution Reduction)

Neutral Density filter  and so on…

Now here’s an image of the pillars of creation captured in various filters:

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Observe that the maximum number of stars are visible in the B, V and r’(infrared) filters. Therefore, combining these three image yields a standard image like the one you find online.

That being said, in our next post, we will run through a quick tutorial on how to access the Hubble archive and retrieve any image with any filter of your choice.

Have a good one!

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The Crab Pulsar (PSR B0531+21) is a relatively young neutron star. The
star is the central star in the Crab Nebula, a remnant of the supernova
SN 1054, which was widely observed on Earth in the year 1054.Discovered
in 1968, the pulsar was the first to be connected with a supernova
remnant.

The optical pulsar is roughly 20 km in diameter and the pulsar
“beams” rotate once every 33 milliseconds, or 30 times each second

The above video allows you to hear the signal from pulsar and the gif below that is the actual pulsar blinking taken with a high speed technique known as  Lucky Imaging .

Supernova Sorcerer: Robert Evans

fuckyeahphysica:

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                            Robert Evans with his reflecting telescope

Robert Evans is the world record holder for the most visual discoveries of Supernovae. Although he is a minister of the uniting church in Australia, he is better known in the Astronomy community as one of the ‘best Amateur Astronomers in the world.’

He is accredited for discovering 42 supernovas visually from his backyard!!

But, how on earth does he do it ?

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Having been looking at the cosmos for years on end, Evans has memorized the entire star field and the positions of the galaxies in the night sky.

And as a result of this, he can detect changes in the galaxy simply by looking at them through the telescope.

Why is this remarkable ?

This is truly remarkable for two pivotal reasons:

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A supernova is the explosion of a star. It is the largest explosion that takes place in space.

But spotting a supernova visually is extremely hard! 

To give a perspective on the intricacies of supernova hunting, here is a picture showing the night sky before and after a supernova in Messier-82.

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                                Supernova hunting in Messier-82

And secondly, he gave automated telescopes a run for their money. There are many telescope in recent times that automatically detect hundreds of supernovas every year.

But Evans managed to give them a tough fight in a battle against man and technology with his telescope sorcery.

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A note for budding astronomers

Why I find Evans to be extremely inspiring is because here is an amateur astronomer doing quality contributions to Astronomy in his backyard and with not so fancy equipment.

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Just shows how far passion and perseverance can take you in science.

Be limitless! Have a great day!

Yesterday’s post: Spectacular time-lapse from birth to death of a Supernova

fuckyeahphysica:

The Tale of Earth and it’s sister Theia.

Have you found it weird that the earth’s axis is tilted by 23.5 degrees and wondered what led to this? Wait, Where did the moon come from?

Well, Here’s what scientists have theorized.

The Giant Impact Hypothesis

Theia, a mars sized planet collided ( it glanced and thankfully did not collide head on, else it would have destroyed earth ) with the Earth around 4.553 billion years ago.

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Theia’s debris gathered together around Earth to form what we now call- The Moon.

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The collision between the early earth and Theia was so immense that
it tilted the axis of rotation of the early earth by 23.5 degrees.

And
it remains tilted so that way even today!!

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Why do they believe in this hypothesis ?

Scientists have a very good reason to believe in the Giant Impact Hypothesis:

  • Earth’s spin and the Moon’s orbit have similar orientations.
  • Moon samples indicate that the Moon once had a molten surface.
  • The Moon has a relatively small iron core.
  • The Moon has a lower density than Earth.
  • Evidence exists of similar collisions in other star systems (that result in debris disks).
  • Giant collisions are consistent with the leading theories of the formation of the solar system.
  • The stable-isotope ratios of lunar and terrestrial rock are identical, implying a common origin
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Have a good day !

PC: sarice,

Now not only do we now have an understanding of why the earth is spinning but also why the axis of rotation is inclined by 23.5 degrees.

Stay tuned for more..

Is the moon on Conan ‘O’ Brian show accurate ?

Haha.. I really appreciate the fact that you were curious about the moon’s photograph that is featured on a late night talk show. 

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Conan the talk show premiered on November 8, 2010. But it was a waxing crescent on November 8,2010 at 11:00 pm, Los Angeles CA.

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And if one were to be really nitpicky about this,by 6:30pm on November 8, 2010 the moon would have already set and you most certainly would not see the moon on the night sky at 11pm.

Therefore, not really sure what the moon is trying to represent here.

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Also the moon keeps changing its orientation over the course of one day. And if you decided to look at the moon each day at the same time , it would be look slightly different.

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                              Moon over the course of 24 hours

But the moon on Conan’s show is mostly Static.

Unless he decides to replace the already ridiculously big moon (Diameter: 3,475 km) that only is supposed to occupy ~0.00106% of the celestial hemisphere in the night sky by a Death Star (Diameter: 100 km to 160km ) of the same size!

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So.. I guess that answers your question.. Have a good one!

Try bringing two of your fingers closer in the back drop of a light source and you would observe this:

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Long before your fingers actually touch, the edges magically seem to touch each other. How is this even possible?

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Transit of Venus

When scientists were observing the transit of Venus from Earth i.e when the planet Venus passes directly between the Sun and Earth,they faced a similar problem. 

At the moment when Venus should
nearly touch the edge of the sun, the circular planet began to elongate.

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                                                PC: NASA

And they noticed the same phenomenon for Mercury as well (which has no atmosphere).


What is causing this optical phenomenon?

The physics behind this beautifully bizarre optical phenomenon will be revealed tomorrow on FYP!.

But since this is something that you can all try at home, we strongly encourage you to play around with this and get a feel for it. It requires only your hands and a source of light.

Once you do, try to hypothesize  a solution for this behavior.

Have fun!

How do you place a satellite in orbit?

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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

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(b) Speed of cannonball ~7300 m/s —-> Circular orbit

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( c) Speed of cannonball ~8000 m/s —-> Elliptical orbit

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(d) Speed of cannonball ~11200 m/s —-> Parabolic trajectory

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(e) Speed of cannonball – Crazy

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Gunpowders are not that powerful !

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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.

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This applies to the ISS as well: “ISS is always falling; Falling into orbit.

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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.

Have a good one!

** TRY IT OUT – Newton’s Cannon