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.
** Just to be really clear, this is not the first time we are launching “automobiles” to space.
Lunar Roving Vehicle
Just to give a perspective on how tiny Mount Everest is compared to
Earth : Mount Everest is 8850m high and the radius of the earth ~6400km.
It is only 0.1% of the radius of the earth.
But surely it does cast a shadow on the moon no doubt about it, but you just can’t see it.
If you took a look at the recent solar eclipse animations by NASA, then you might have noticed the shadows cast by the moon during the eclipse were not circular (like yesteryears – see figure above).
But had an eerie irregular shape to it. Why is that ?
First thing to note is that if you take a circle and project it on a sphere, the shadow is no longer circles, but ellipses.* That’s why the image is elongated.
Importantly, the surface of the moon is interesting; It is irregular with lots of mountains and valleys. Hence you will not get a perfect little ellipse when you project it.
Based on whether it is a valley or a peak it would affect the shadow region during an eclipse.
As
mentioned in a previous post, eclipses on earth are too surreal to be
true because if the size of the moon were any bigger then you would be
witnessing only perfect elliptic shadows and none of this complex mess.
But if the moon’s valley were any bigger, you might never achieve complete totality.
Amazing Question. Thanks for asking!
* Unless you project it face onto the source
Here you go:
Davis, California
Paris, France
Bengaluru, India
Sydney, Australia
Have a great week!
**Made with Stellarium
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.
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.
Great Question. Thanks for asking !
** For more information. check out this TED talk
– Seen at the Chabot Space & Science Center
Last few hours to get your name etched onto a microchip which will land on mars!
Closing time: 11:59 p.m. ET, November 1
A processed image of Jupiter from JunoCam
JunoCam
is a visible-light camera/telescope placed on the Juno Jupiter Orbiter.
But the cool part about this is that it was primarily put on board the
orbiter primarily for public science and outreach.
If you are
an amateur astronomer and also interested in image processing, you have
full access to all the raw images taken by the orbiter (check link).
Have fun!
Place: Jupiter
Years: 1997 – 2000
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
TL;DR:
DE + BC —> BE ;
BE + FA —> BA ;
( True story ! )
Now if you were like me, this might come to you as a huge surprise because whenever one thinks about Jupiter one is not used to visualizing it with rings around it, but rather as a huge gas giant.
Unlike Saturn’ rings which are bright, the discovery of Jupiter’s wings had to wait till 1979.
This is so because the rings are faint and are only visible only when viewed behind Jupiter and lit up by the sun.
Jupiter’s rings are formed from dust particles hurled up by micro-meteor
impacts on Jupiter’s small inner moons and captured into orbit.
If the
impacts on the moons were any larger, then the larger dust thrown up
would be pulled back down to the moon’s surface by gravity (meaning that the dust would not have enough velocity to escape the surface).
The main and halo rings consist of dust ejected from the moons Metis, Adrastea, and other unobserved parent bodies as the result of high-velocity impacts
The rings
must constantly be replenished with new dust from the moons to exist.
Actually, there are quite a bit about these rings that we are still in the dark about. And hopefully these would become clearer in the upcoming years.
Have a great day!
Ecstasy Shots 