Week 3

Lecture 2

Dawn mission- was a novel mission because it was the first to make use of ion propulsion instead of having fuels ion propulsion takes gasses in like argon or zenon. All they need is solar panels to get electricity then those ions end up being used for energy.

Vesta before dawn- imagine a horrible resolution of the rock and now we are able to interpret all of the cratering and some carbon rich material. Has a dieameter of around 550 km or 342 miles and mean density= 3420. Gravity high happens when you have an impact- large mass of material from deeper in the body to the surface, the dreadging up of dense material the densert the material you have more mass. The strongest graviry is in read, in impact craters you see higher levels of gravity. More density more force.

The outer part of the body is made up of basalt- the same type of material that makes up the hawian volaccnoes, the bottom of the sea floor. Basalt is all over the place- in sea, space. Basalt is a very common igneous rock so it is not surprising that we would see it here.

HED meterories-

howardites- clasts of eucrite and digogentie material

eucites- plagioclase + pyroxene (basalt), crust, the things that melt ot make a solid. We can understand the types of process happening because we can determine what happned.

digenties- orthoprrene > plag +olivine deeper crust, mantle

Rock/metal differentiation- vesta must have had molten lava inside.

Ceres- more massive, has a diameter twice that of vesta ( 950 km) mean density = 2160. Less dense meteorite having not been melted showcases lots of interesing rocks. We see that muddy slaty water must have flowed outside of these craters. Salt (sodioum choloride) oxygen atoms with other elements took inbetween. These are all the things that happens to rock when faced with warm water. So we have evidence.

Cere’s surface- at one point ceres was though t have frost on its surface though this looks unlikely there is still a strong case for water: what is there- clays, brucite, mg sulfates, and nh4 (amonia)(all made by weathering rock). possibilities. Bright spots- outgassing. Criovolcano present- slat water, mid, ice and sodim carbonate active around 100 years ago. Really big on ceres has streaks of white stuff indicating that this is a cryovolcao.

Ceres is very interstesign becasue it has lots of salty things on the surface, the thoghotu being that this is a current day ocean floor, water ice (since removed. As you go deeper below the ice there may have been enough heat flor an intermignle creating a rock mantle.

ceres did not get to a high enough temperature to melt rocks- whent thoruhg ice series differntation. Did melt the ice and water forming an icy shell. Vesta- wen through rock metal differntations. Biggest asteroid is the belt about the size of the state of texas.

psyche- the asteroid and discovery mission headed toward psyche- m type asteroid= metal very much highly reflective.

Where did the heat come from to melt asteroids- what melted vesta- the sun got hot becasue of taking gravitational energy and turning it to kinetic energy. So one the first thing could ceris or vesta have heated up becasue of gravitational collaspe. U collaspe = - 3gm divided by 5r. Temperture required tomelt rock- 1273, there needed to be a heat soruce that was sufficent to heat it up to 1300 degrees and gravity wasn’t enough.

Harold Urey- won the nobel for deteruium, one of the first people who established planetrary science- maybe the heat source came from aluminum specifically alumninum 26 have has half life at the rate tha twould disappear millions of years ago. Has very prominent heat production. Turns out we can make maps of aluminum 26 as it gives off a gamma ray when it decays (1.8 mev). wolfray stars- spit out massive amounts of alumninum 26, so if we form in a star forming region where there was tons of stars we should have recieved aluminum 26. It is indeed the source of heat as we find mg 26 the byproduct of the decay of of al 26 meaning that this was the heat source.

We know that vesta had to have had formed early enough to have been lots of aluminum preesent. Metalic core of iron and nickel. surface baslat, mantle kidn of basalt that was affected by aluminum 26.

Evolution of icy plantetsimals in the early solar system- when you get larger you trap the heat from the al 26. if they are large enough they are going to melt. The higher the surface area to volume the better you radiate away. So the smaller the sphere is the lower the volume area is. Being later the lcoaezed hydrou alteration and metapmorhims, h20 never melts because a26 never coinsided with the existence of ceris.

1400 potentially hazardous eath orbit crossing, we do have an asteroid or commit from outside our solar system called onumuamua. Was discovered in Hawaii it pans areound the sun it goes so fast that it just passes through the sun. shape that this was like a ciggar. 115 × 111×19 meters in size

Comets- the very oldest materials had al 26 so they melted and they had volcanism they were igneoous. Vesta is older than comets more developed. basics about commites they have two tails- blue part is made of solar protons coming from the sun. tails get longer the closer a comet gets to a sun. always points away from a star. Tails are always directed away from the sun. Gas ion tails points traight away from the sun. Dust tail curves toward orbital path .Expercencies mroe gravitational pull, thends to migrate toward the gravitaitnal pull making a gap between the two tails

Comets follow different orbits- some that come around certain times in a life time, some that we will never see untilthousands of years some we see every other years. We can categorize those who are shorter coming from the kuiper belt from 30 to 50 au from the sun. It is the soruces of lots of commets.

In 1950- Jan oort noticed that- no comet has been observed with an orbit that indcates that it came from intersetllar space not ture anymore. there is strong tendecy for apheial of long perod commet orbits to lie at a distance about 50,000 au and ther is no perferential direction which commets. The oort cloud is where comets who are very far away from being around 50,000 from the sun.

short period comets: orbit periods less than 20 years orgins from the kuiper beot with orbits influeced by juoiper owth appheali orbit of jupiter

Mission to tempel 1- one of the modern mission to a comet- tempel 1 being short period comit, with a much more circular orbit. Deep impact that went to tempel 1- deep imact strageically encouted tempel 1 and crashed into it on the 4th of july in 2004. comets- are kind of giant balls of ice but now we know that they are icy dirtballs they ahve more dirt than ice that we thought.

Rosetta (ESA) went to comet 67 p- two lobes big debate is whether these things were just touching and got stuck or is it that all the stuff in the middle is more prone to stay away from the sun so it got stuck together. Wanted to meet the comet farther from the sun becasue when clsoer it starts spewing out material meaning a danger to the tech. the tails happens in events not continuously. Sublimation femurs- similar patterns in the snow. sublimination- when you go from solid to vapor. solid is turning into vapor directly.

Phale lander caputed by orisis camea on roettea- have harpoons that would stick on they fail and they bounce across the surface becasuse of such low amounts of gravity.

Stardust- comet wild 2 as seen from stardust spacecraft- was analzyed at ucla- was a space craft that had a big paddle- in the paddle inside was aerogel. Like a super air sponge. incredbily strong for how light it iwas. the idea is that all the stuff coming off the comet would be stuck in the arogel, these little parts of comet come off and land back and seeking all of that stuff we still see peopl study ing the little bits of cmet from this mission.

Lab 1 10/17 Solar Wednesday- happens noon 12 pm to 1pm at the court of sciences- make up one of the lost labs.

Kepler’s law- for the very last days of his life he was much more of a theory based person, he was able to come up with some of the laws that we stillknow that are valid today. Everything in the uniberse is governed by some universal lawsw when talking aobut plantary motion we need to think that these laws apply to every where we know.

Kepler’s laws include: all planets don’t move in circulate movements but instead in elliptical orbits that sun is located in one of the focal points of the ellipse. Elipses these points are called the focal points there is always an F1 and F2.

Perihelion and Aphelion- the second law : planets revolving the sun or any central mass will sweep out equal amounts of area in equal interval of times.

Third law: the square of the orbital period of a planet is proportional to the cube of its distance from the sun.