Thoughts On Revisting Venus

Radar Image of the surface of Venus, centered at 180 degrees east longitude. Magellan imaging 1990-94

via reddit

Daily Science Dump: Kepler’s First Law Edition

Bonjour my science nerds. I got a question regarding Kepler’s Three Laws because they can be somewhat confusing. And tbh, they really are. Because they can be a bit of a pain, I’ve decided to break this up into 3 sections, one for each law. They generally follow the same idea: planetary orbits are not circular. The difference between each law resides in the minute details. And because they are really detailed, I wanted to make sure I covered everything of each law so they don’t get confused. Let’s get started!

Kepler’s First Law of Planetary Motion

History

Before we get into the actual laws, we need to understand why these laws are so important. During the 1500s and early 1600s, astronomy was starting to become a big deal. We were trying to figure out where we are in the universe. During this time period, the famous geocentric and heliocentric models were stirring up massive controversy in the Catholic Church (for obvious reasons). Ptolemy brought around the geocentric model, which put Earth at the center. This was a natural thought at the time because it was a religious concept that man was God’s greatest creation, so God would want to put man at the center of everything (little presumptuous on our part tbh). Next, Copernicus said that our Sun was in the center, and all the planets orbit around the sun. This clearly didn’t go down well with the Church because it was the first instance of defying the Catholic Church, therefore defying God. In an attempt to settle down the controversy, Brahe brought around a new theory model, putting the Earth at the center, having the Sun and Moon orbiting the Earth, and then the rest of the planets orbiting the Sun. It was a very far reached model but people bought it. All of these models had one thing in common; all the orbits of the planets were circular. But none of none of the actual data fit with perfect circular orbits. This is where our boi Kepler comes in. 

It was long believed that the planets should orbit along circular paths, because a circle is considered an ideal shape. But as I mentioned before, none of the data was fitting the circular shape, particularly Mars. Kepler brought around another shape, the ellipse, to explain the missing pieces of the data. An ellipse is like a flattened circle with some important properties that Kepler used for his laws. His first law focuses more on explaining the patterns of elliptical orbits. The second and third law goes into more detail on the properties of elliptical orbits. 

If you’ve taken a simple geometry class, you know the basic principles of ellipses. We know there’s a major-axis and minor-axis (the diameter horizontally and the diameter vertically), the focal points, and eccentricity. All of these are important for planetary orbits. If we take a trip back to geometry, we know that the positions of the focal points affect the eccentricity, which is basically how much it’s being squished (if e = 0 then it’s a perfect circle and if e = 1 it’s a parabola). 

All of this geometry going on transfers over into planetary motion. In this case, the Sun acts as one of the focal points. The other focal point is merely imaginary. Mathematically it exists but there’s nothing at that point in space that says “Hey! I’m a focal point for Saturn!”. But we know for sure that the Sun is on of the two focal points. This revelation caused a lot of uproar and many refused to believe it. Partly because the orbit of a lot planets are so close to a perfect circle it’s extremely hard to tell it’s elliptical at all. 

Eccentricity has to stay between 0 and 1, like I explained earlier. An eccentricity of 0 is a perfect circle. If it’s 1 or greater, it’s a parabola. For the planetary motion, most of the planets’ eccentricity doesn’t even crack 0.1 (Pluto has a bit over 0.2 but apparently Pluto isn’t a planet #JusticeForPluto). Earth’s eccentricity is currently 0.0167, which means its very very close to a perfect circle. But not quite. To be quite honest, the fact that Kepler was able to figure out that the orbits were not circular is astonishing.

So that’s it for Kepler’s First Law of Planetary Motion! These laws were critical in understanding how our universe works and how our solar system plays out. It opened our eyes to many new ideas and thought processes. This law is just the first step of understanding the orbital tendencies of planets. On Friday, we will dive right into Kepler’s Second Law of Planetary Motion which goes into detail about the speed of the planet due to the elliptical orbit.

Don’t forget, I’m updating the Blog Website everyday with something new because I have no life…. I added cool space music! If you have any cool song recommendations for the playlist definitely shoot me a message!

If you have any questions about today’s Daily Science Dump or any past ones, don’t be afraid to ask!

As always,

Stay Nerdy!

R.L.

Solar System

•please like or reblog if you use

The sky seemed to smile over much of planet Earth. Visible the world over was an unusual superposition of our Moon and the planets Venus and Jupiter. A crescent Moon over Los Angeles appears to be a smile when paired with the planetary conjunction of seemingly nearby Jupiter and Venus.

A couple of you have given us great topic ideas for inforgraphics, but if there is anything else that comes to your mind just let us know. Also if you are interested in printing this as a poster for your class send us an email to lthmathematics@gmail.com so we can send you a pdf (easy for print).

Craters on Venus.

ASTEROID DAY 2018

On 30 June 1908, 110 years ago, a 40 m asteroid struck the Earth over Tunguska, Siberia.

Destroying an area of forest the size of Greater London, this was the most significant impact event in Earth’s recent history.

Now recognised by the United Nations as Asteroid Day, 30 June marks a global opportunity to raise awareness of the threat and opportunity posed by the numerous rocky bodies traversing space.

Since 2009, ESA has played a leading role in the global hunt for risky asteroids and comets – known formally to astronomers as near-Earth objects (NEO) – and is currently developing cutting-edge widefield telescopes that will have the ability to scan the entire sky in just 48 hours.

ESA also carries out crucial analysis as part of its Space Situational Awareness (SSA) programme and mobilises observatories and astronomers worldwide through its SSA NEO Coordination Centre at the Agency’s ESRIN facility in Italy.

Each year, Asteroid Day is broadcast live across the globe with a packed programme that brings together astronauts, rock stars and scientists.

Highlighting our potentially vulnerable place in space, the live event also describes the many ingenious and yet not-far-from scifi potential solutions to these dangerous roaming rocks.

Each year hundreds of regional events also take place, with 78 countries so far having hosted concerts, community events, lectures and much more.

Venus as seen from the Mariner 10 probe taken in 1974

NASA Study Proposes Airships & Cloud Cities for Venus Exploration

The surface of Venus isn’t going to work for humans, but what if we ignore the surface and stick to the clouds? Dale Arney and Chris Jones, from the Space Mission Analysis Branch of NASA’s Systems Analysis and Concepts Directorate at Langley Research Center, in Virginia, have been exploring that idea. Perhaps humans could ride through the upper atmosphere of Venus in a solar-powered airship. Arney and Jones propose that it may make sense to go to Venus before we ever send humans to Mars.

http://spectrum.ieee.org/aerospace/space-flight/nasa-study-proposes-airships-cloud-cities-for-venus-exploration

Meet Bruce McCandless. He was a bit of a bad-ass. In 1984, Bruce was aboard the Challenger Space Shuttle and became the first human to walk in space without a safety line. By utilising a nitrogen propelled Manned Maneuvering Unit (MMU), he stepped free from Challenger into the blackness of space for a 90-minute space walk and wandered as far as 97 meters from the ship. The result is this amazing image which captures ingenuity, innovation and most certainly bravery.

Bruce McCandless died yesterday at the age of 80.

-Jean Image Credit: NASA