Bruce McCandless II (June 8, 1937 – December 21, 2017)

"NASA Langley researchers want to get a better idea about conditions on our nearest planetary neighbor, Venus, so they have come up with HAVOC or a High Altitude Venus Operational Concept – a lighter-than-air rocket ship that would help send two astronauts on a 30-day mission to explore the planet’s atmosphere. Exploration of Venus is a challenge not only because its smog-like sulfuric acid-laced atmosphere, but also its extremely hot surface temperature and extremely high air pressure on the surface."  

"The video shows a human mission that’s part of a multi-phase campaign to explore and potentially settle Venus. Before the mission in the video occurred, there would be similar robotic missions to test the technologies and better understand the atmosphere. Eventually, a short duration human mission would allow us to gain experience having humans live at another world, with the hope that it would someday be possible to live in the atmosphere permanently (hinted at in the closing shot of the video)."

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.

“Venus at Night in Infrared from Akatsuki” Is the NASA Astronomy Picture of the Day of today, January 30, 2018

Wind hitting Venus’s mountains makes the planet rotate faster

Turbulent atmosphere speeds Venus’s days by a full 2 minutes

Venusian mountains impact its rotation

Why We Need to Get Back to Venus

Paul Byrne explains why we need to get back to our cosmic neighbor.

Thoughts on revisting Venus

So NASA won the internet today…

Ten interesting facts about Mars

The ancient Sumerians believed that Mars was Nergal, the god of war and plague. During Sumerian times, Nergal was a minor deity of little significance, but, during later times, his main cult center was the city of Nineveh. In Mesopotamian texts, Mars is referred to as the “star of judgement of the fate of the dead”. The existence of Mars as a wandering object in the night sky was recorded by the ancient Egyptian astronomers and, by 1534 BCE, they were familiar with the retrograde motion of the planet. By the period of the Neo-Babylonian Empire, the Babylonian astronomers were making regular records of the positions of the planets and systematic observations of their behavior. For Mars, they knew that the planet made 37 synodic periods, or 42 circuits of the zodiac, every 79 years. They invented arithmetic methods for making minor corrections to the predicted positions of the planets.

Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System after Mercury.

The bright rust color Mars is known for is due to iron-rich minerals in its regolith — the loose dust and rock covering its surface. The soil of Earth is a kind of regolith, albeit one loaded with organic content. According to NASA, the iron minerals oxidize, or rust, causing the soil to look red.

The rotational period and seasonal cycles of Mars are likewise similar to those of Earth, as is the tilt that produces the seasons. Mars is the site of Olympus Mons, the largest volcano and second-highest known mountain in the Solar System, and of Valles Marineris, one of the largest canyons in the Solar System.

Mars has two moons, Phobos and Deimos, which are small and irregularly shaped. These may be captured asteroids, similar to 5261 Eureka, a Mars trojan.

There are ongoing investigations assessing the past habitability potential of Mars, as well as the possibility of extant life. Future astrobiology missions are planned, including the Mars 2020 and ExoMars rovers. Liquid water cannot exist on the surface of Mars due to low atmospheric pressure, which is less than 1% of the Earth’s, except at the lowest elevations for short periods. The two polar ice caps appear to be made largely of water. The volume of water ice in the south polar ice cap, if melted, would be sufficient to cover the entire planetary surface to a depth of 11 meters (36 ft). In November 2016, NASA reported finding a large amount of underground ice in the Utopia Planitia region of Mars. The volume of water detected has been estimated to be equivalent to the volume of water in Lake Superior.

Mars can easily be seen from Earth with the naked eye, as can its reddish coloring. Its apparent magnitude reaches −2.91, which is surpassed only by Jupiter, Venus, the Moon, and the Sun. Optical ground-based telescopes are typically limited to resolving features about 300 kilometers (190 mi) across when Earth and Mars are closest because of Earth’s atmosphere.

Like Earth, Mars has differentiated into a dense metallic core overlaid by less dense materials. Current models of its interior imply a core with a radius of about 1,794 ± 65 kilometers (1,115 ± 40 mi), consisting primarily of iron and nickel with about 16–17% sulfur. This iron(II) sulfide core is thought to be twice as rich in lighter elements as Earth’s. The core is surrounded by a silicate mantle that formed many of the tectonic and volcanic features on the planet, but it appears to be dormant. Besides silicon and oxygen, the most abundant elements in the Martian crust are iron, magnesium, aluminum, calcium, and potassium. The average thickness of the planet’s crust is about 50 km (31 mi), with a maximum thickness of 125 km (78 mi). Earth’s crust averages 40 km (25 mi).

Mars lost its magnetosphere 4 billion years ago, possibly because of numerous asteroid strikes, so the solar wind interacts directly with the Martian ionosphere, lowering the atmospheric density by stripping away atoms from the outer layer. Both Mars Global Surveyor and Mars Expresshave detected ionised atmospheric particles trailing off into space behind Mars, and this atmospheric loss is being studied by the MAVEN orbiter. Compared to Earth, the atmosphere of Mars is quite rarefied.

Mars’s average distance from the Sun is roughly 230 million kilometres (143,000,000 mi), and its orbital period is 687 (Earth) days. The solar day (or sol) on Mars is only slightly longer than an Earth day: 24 hours, 39 minutes, and 35.244 seconds. A Martian year is equal to 1.8809 Earth years, or 1 year, 320 days, and 18.2 hours

Mars is scarred by a number of impact craters: a total of 43,000 craters with a diameter of 5 km (3.1 mi) or greater have been found. The largest confirmed of these is the Hellas impact basin, a light albedo feature clearly visible from Earth. Due to the smaller mass of Mars, the probability of an object colliding with the planet is about half that of Earth. Mars is located closer to the asteroid belt, so it has an increased chance of being struck by materials from that source. Mars is more likely to be struck by short-period comets, i.e., those that lie within the orbit of Jupiter. In spite of this, there are far fewer craters on Mars compared with the Moon, because the atmosphere of Mars provides protection against small meteors and surface modifying processes have erased some craters.

Martian craters can have a morphology that suggests the ground became wet after the meteor impacted.

Source 1

Source 2

images: NASA/JPL-Caltech/Univ. of Arizona , ESA, Tunç Tezel

astronomy facts

Pioneer Venus Artwork

Artist’s concept of Pioneer Venus mission approaching the planet.

During a 14-year orbit of Venus, Pioneer Venus 1 used radar to map the surface at a resolution of 75 km (47 miles). It found the planet to be generally smoother than Earth, though with a mountain higher than Mt. Everest and a chasm deeper than the Grand Canyon. The orbiter also found Venus to be more spherical than Earth, consistent with the planet’s much slower rotation rate (one Venus day equals 243 Earth days). It confirmed that Venus has little, if any, magnetic field and found the clouds to consist mainly of sulfuric acid. Measurements of this chemical’s decline in the atmosphere over the course of the mission suggested that the spacecraft arrived soon after a large volcanic eruption, which may also account for the prodigious lightning it observed.

After a course correction on 16 August 1978, Pioneer Venus 2 released the 1.5-m diameter large probe on 16 November 1978, at about 11.1 million km from the planet. Four days later, the bus released the three small probes while 9.3 million km from Venus. All five components reached the Venusian atmosphere on 9 December 1978, with the large probe entering first.

Data from the probes indicated that between 10 and 50 km, there is almost no convection in the Venusian atmosphere. Below a haze layer at 30 km, the atmosphere appears to be relatively clear. Amazingly, two of three probes survived the hard impact. The so-called Day Probe transmitted data from the surface for 67.5 minutes before succumbing to the high temperatures and power depletion.

Credit: NASA/Rick Guidice

Earth View from Moon by ric tan

Image of the clouds of Venus via the European Space Agency

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