Spectacular Planetary And Lunar Alignment To Grace The Post-Sunset Thanksgiving Skies
“As 2019 has progressed, Saturn has followed Jupiter in its sky-crossing migration from east to west. Meanwhile, for about the past month, Venus has emerged as an evening star after sunset, drifting from west to east. On Sunday, November 24, Venus and Jupiter nearly met — achieving a conjunction — coming within 1.4° of each other.”
Normally, astronomical conjunctions are a big and spectacular deal, especially when they’re close, and particularly when they’re between the two brightest planets of all: Venus and Jupiter. But on American Thanksgiving, November 28, an extraordinary and unusual event will occur: the young crescent Moon will align with Venus and Jupiter as well, fresh off a conjunction. While skywatchers worldwide will get a spectacular show, the best views come for people in European and African longitudes, as they’ll see the Moon appear between closely spaced Venus and Jupiter.
What Was It Like When Venus And Mars Became Uninhabitable Planets?
“But the changes that Mars endured were rapid and sweeping. Planets are born with a fixed amount of internal heat, which radiates away over their lifetime. A planet like Mars, with half the diameter of Earth, is born with only about 10-15% the amount of internal heat as our world, and will therefore see a greater percentage of it radiate away much faster than Earth will.
Approximately 3 billion years ago, the core of Mars became cool enough that it stopped producing that protective magnetic dynamo, and the solar wind began striking the Martian atmosphere. In short order, which is to say in just tens of millions of years, the atmosphere was knocked off into interplanetary space. As a result, the oceans were unable to remain in liquid form, and either froze beneath the surface or sublimated away.”
When our Solar System first formed, it wasn’t just Earth that looked promising for life, but also Venus and Mars. All three of these planets had large, liquid water oceans, substantial atmospheres, and the ingredients for complex biochemistry and even life. Over on Venus, its close proximity to the Sun and the large presence of atmospheric water vapor led to a runaway greenhouse effect, boiling the oceans after just ~200 million years. But Mars, despite being small and distant, maintained Earth-like conditions for 1.5 billion years. Considering that life arose on Earth after just one-sixth of that duration, perhaps Mars once had life, too?
Try bringing two of your fingers closer in the back drop of a light source and you would observe this:
Long before your fingers actually touch, the edges magically seem to touch each other. How is this even possible?
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.
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.
The black drop effect
Let’s take a closer look at this optical phenomenon by projecting your hand on to a screen and bringing the fingers closer together.
Observe the behavior of the penumbral region of the shadow i.e the less darker region:
Ahhaa… Notice that even though my fingers are not touching each other in the last image, if you see the shadow it seems as though they are!
This is because of when two penumbral regions of the shadow overlap, you get a much darker region in the middle. Here’s an illustration:
Yes in reality, you do observe gradients of darkness in between the two objects like so:
BUT our eyes are not that great at handling such fine contrasts in darkness; It clips off the less darker regions between the two shadows and replaces it with the surrounding darker region.
A similar response is rendered by the camera’s noise suppression algorithm too. That’s why you get that bulge connecting the two umbras irrespective whether you view it through your eye or through the camera.
In the case of the camera, this can be rectified using the appropriate tools and processing, whereas in the case of the eye you are stuck with it.
The case for Venus Transit
You can observe the same clipping phenomenon (called Black drop effect) that we talked about if we project the image onto a camera instead of a screen:
If the light source were the sun, the object were Venus instead of your fingers, and the screen were your eyes, you get this fuzzy shadow behavior commonly observed during the transit of Venus.
This is not a droplet, but the black drop effect observed during the transit of Venus
The case for Diffraction (OPEN DISCUSSION):
When I posed this question to a lot of my friends, their first response was Diffraction but honestly I couldn’t visualize this phenomenon with Diffraction.
I spent a lot of time playing with a laser module trying to figure out how Diffraction would fit into this explained but I am unable to come up with a reasonable argument for it.
If you have a valid explanation of this using Diffraction(or other), please enlighten me and the rest of the community. I personally would really love to know.
Eight Other Worlds In Our Solar System Might Have Life Beyond Earth
“5.) Venus. Venus is hell, literally. At a constant surface temperature of some 900 degrees Fahrenheit, no human-made lander has ever survived more than a couple of hours while touched down on our nearest neighboring planet. But the reason Venus is so hot is because of it’s thick, carbon-dioxide rich atmosphere laden with heat-trapping clouds of sulphuric acid. This renders the surface of Venus thoroughly inhospitable, but the surface isn’t the only place to look for life. In fact, speculation is rampant that perhaps something interesting is happening some 60 miles up! Above the cloud-tops of Venus, the environment is surprisingly Earth-like: similar temperatures, pressures, and less corrosive material. It’s conceivable that with its own unique chemical history, that environment is filled with carbon-based airborne life, something that a mission to Venus’ upper atmosphere could easily sniff out.”
The Earth, to the best of our knowledge, is the only inhabited world we have. The ingredients for life may be everywhere, from asteroids to nebulae to exoplanets and more, but so far, only Earth is confirmed to have life. While Earth-like planets around Sun-like stars at the right distance for liquid water on their surface might seem like the best place to look for life, we don’t necessarily need to go that far. Right here in our own cosmic backyard, our own solar system boasts eight potential candidates for worlds with life on them today. Some of them are planets, like Mars and Venus; others are moons, like Europa and Titan; even asteroids like Ceres or Kuiper belt objects like Pluto get in on the action. The life that might be present might not look like most of life on Earth, but unless we look at the likely locations of biological activity in situ, we simply won’t know for certain.