Speed Quiz with Why

This week is going to be slightly more challenging, as I’ve included harder questions and for some – you’ll need to explain why.

The binary star Algol consists of a 3.7M sun main sequence star and a 0.8 M sun subgiant star.  What’s odd about this pairing? 

Stars are close enough that matter can flow from the sub-giant onto the main sequence star.  The star that is now a subgiant was originally more massive.  As it reached the end of its life and began to grow, it transferred mass to its companion star (mass exchange- can alter lives of stars w/ close companions).

Stages of low-mass star:

H to He in core, H to He fusion in shell around contracting core, He to C fusion in core, double-shell burning – becomes white dwarf (protostar, main-sequence, red giant, white dwarf)

Stages of high-mass star:

same as low-mass, multiple shell burning, supernova (iron core collapses) – becomes neutron star, black hole, or nothing.

Suppose that we look at a photograph of many galaxies. Assuming that all galaxies formed at about the same time, which galaxy in the picture is the youngest?

The one that is farthest away

What are the necessities for life?

Nutrients, energy, liquid water

What clues to our galaxy’s history do halo stars hold?

They’re all old, w/ a smaller portion of heavy elements than disk stars, indicating that halos formed 1st.

What lies in the center of our galaxy?

Orbits of stas near the center of our galaxy indicate the existence of a black hole w/ 4 million times the mass of the sun.

What might dark matter be made of? 

There does not seem to be enough normal (baryonic) matter to account for all the dark matter, so it is probably made of particles that haven’t been discovered yet (non-baryonic).

What force keeps you from sinking to the center of the Earth? 

Magnetism

What were conditions like in the early universe? 

It was so hot and dense that radiation was constantly producing particle-antiparticle pairs.

What aspects of the universe were originally unexplained by the Big Bang Theory? 

The origin of structure, the smoothness of the universe on large scales, the nearly critical density of the universe.

What is the history of the universe according to the Big Bang? 

As the universe cooled, particle production stopped, leaving matter instead of anti-matter.  Fusion turned the remaining neutrons into helium.

Radiation traveled freely after the formation of atoms.

What causes gamma-ray bursts?

At least some come from supernova explosions.

What does our galaxy look like?

Our galaxy consists of a disk of stars and gas, w/ a bulge of stars at the center of the disk, surrounded by a large spherical halo.

What causes solar activity?

The stretching and twisting of magnetic field lines near the sun’s surface causes solar activity.

What is the sun’s structure?

Layers from inside out: core, radiation zone, convection zone, photosphere, chromosphere, corona.

What would happen inside the sun if a slight rise in core temp led to a rapid rise in fusion energy?

The core would expand and cool.

Why?  Decline in core temp causes the fusion rate to drop, so the core contracts and heats up.  Rise in core temp causes fusion rate to rise, so core expands and cools down.

What are the 2 types of star clusters? 

Open clusters are loosely packed and contain up to a few thousand stars.  They range in age from <10 million years old to >7 billion years old.  Globular clusters are densely packed and contain hundreds of thousands of stars that are about 1 billion years old.

What would happen to a contracting cloud fragment if it were not able to radiate away its thermal energy?

It’s internal pressure would increase.

Why?

The cloud can prevent a pressure buildup by releasing heat (by converting thermal energy into infrared and radio photons that escape the cloud).

What would happen to a protostar that formed w/o any rotation at all? 

It would not have any planets because planets need to rotate in order to be accreted.

What happens when a star can no longer fuse H to He in its core? 

Core will shrink and heat up.

Post today sponsored by the Top Tree Removal Experts in Albany, NY.  Visit their website for more information.

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Return of the Speed Quiz

How do we measure stellar luminosities?  If we measure a star’s apparent brightness and distance, we can compute its luminosity w/ the inverse square law for light.  Parallax tells us distances

to the nearest stars.

How do we measure stellar temperatures?  A star’s color and spectral type both reflect its temperature.

How do we measure stellar masses?  Newton’s version of Kepler’s 3rd law tells us the total mass of a binary sys. If we can measure the orbital period (p) and avg. orbital separation of the sys (a).

P^2 = ((4x^2)/G(M1+M2))*a^3

How do we measure the age of a star cluster?  A star cluster’s age roughly equals the life expectancy of its most massive stars still on the main sequence.

How do stars form?  Stars are born in cold, relatively dense molecular clouds.  As a cloud fragment collapses under gravity, it becomes a protostar surrounded by a spinning disk of gas.  The

protostar may also fire jets of matter outward along its poles.

How massive are new born stars?  Stars greater than about 150M sun would be so luminous that radiation pressure would blow them apart.  Degeneracy pressure stops the contraction of

objects <0.08M sun before fusion starts.

How does a low-mass star die?  Ejection of H and He in a planetary nebula (and eventually galactic gas) leaves behind an inert white dwarf.

How does a star’s mass determine its life story?  Mass determines how high a star’s core temperature can rise and therefore determines how quickly a star uses its fuel and what kinds of

elements it can make.

How is gas recycled in our galaxy?  Gas from dying stars mix new elements into the interstellar medium which slowly cools, eventually creating molecular clouds where new stars form.

Those stars will eventually return much of their matter to interstellar space.

How does inflation explain these features? (see “What aspects of universe… question)  Structure comes from inflated quantum ripples.  Inflation flattened the curvature of space, bringing

the expansion to rate into balance with the overall density of mass-energy.

How can we test the idea of inflation?  We can compare the structures we see in detailed observations of the microwave background w/ predictions for the “seeds” that should have been planted by inflations.  So far, our

observations of the Universe agree w/ models in which inflation planted the “seeds”.

How do we observe the radiation left over from the Big Bang?  Radiation left over from the Big Bang is now in the form of microwaves- the cosmic microwave background, which we can

observe w/ a radio telescope.

How do the abundances of elements support the Big Bang Theory?  Observations of helium and other light elements agree w/ the predictions for fusion in the theory.

How did life arise on Earth?  Life evolved from a common organism through natural selection, but we do not yet know the origin of the first organism

How many civilizations are out there?  We don’t know, but the Drake equation gives us a framework for thinking about the question.

How does SETI work?  Some telescopes are looking for deliberate communications from other worlds.

How many He nuclei fuse to make C? 3

Pluto is different from the Jovian planets in all of the following ways except which one? It’s surface temperature is very cold

The Sun’s habitable zone extends from some place a little beyond the orbit of Venus to some place near the orbit of Mars.

These 2 stars have about the same luminosity- which is brighter- Alpha Centauri or Sun?  Sun – we judge by apparent brightness, so Sun is brighter.

Big thanks to our friends and partners at Albany Towing Services for being our primary benefactor both on funding research and allowing our site to keep going.  We are very grateful.  They’re the ones to call if you’re in need.

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Weekly Challenge

nuclear fusion

How does nuclear fusion occur in the sun?  The core’s extreme temp and density are just right for the nuclear fusion of hydrogen to helium through the proton-proton chain.  Gravitational equilibrium acts as a thermostat to regulate the core temp b/c the fusion rate is very sensitive to temp.

How does energy from fusion get out of the sun?  Randomly bouncing photons carry it through the radiation zone.  The rising of hot plasma carries energy through the convection zone to the photosphere.

How do we know what is happening inside the sun?  Mathematical models agree w/ observations of solar vibrations and solar neutrinos.

How does solar activity affect humans?  Bursts of charged particles from the sun can disrupt communications, satellites, and electrical power generation.

How does solar activity vary w/ time?  Activity rises and falls in 11-year cycles

How would the apparent brightness of Alpha Centuari change if it were 3x farther away?  1/9 as bright.  Use apparent luminosity equation (3^2 = 9).

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Hubble Space Telescope vs The Generic Brand

The 2.5 billion dollar Hubble Space Telescope was built by NASA and sent into outer space in the early 90’s, carried by a rocket named STS-31.  It was originally supposed to be launched into orbit nearly a decade earlier, but on January 28, 1986, the Challenger rocket disaster occurred.  The Challenger rocket launched and blew up shortly after take-off.  A hot flare burned through the main fuel tank, igniting the oxygen inside the ship and destroying it, killing all 7 astronauts inside and raining pieces of the burning rocket all over the ocean.  Everything was put on hold for months after that.  The Hubble telescope was eventually launched and is still floating around in the darkness today.  It wasn’t the first one to be sent into space, but it is certainly one of the biggest, and it’s been used heavily in the field of astronomy for the past 20 some years.  Over the past 2.5 decades, four missions have been tasked and completed to repair and/or improve the unit, while it was still in space.  This multipurpose super telescope can view things in multiple areas on the electromagnetic spectrum, from visible light to almost ultraviolet and almost infrared.  There is a special institute that sits on the John Hopkins University campus which monitors the telescope 24/7 and provides the data to astronomers.  Because the telescope if floating outside of Earth’s atmosphere, the pictures it’s able to take are crystal clear and frankly tremendous.

Obviously, nothing that the average person can purchase will ever come close to delivering the type of images that Hubble can, but you can still see some amazing shots for a few thousand dollars.  Science has shown that the positioning of the sun and moon during the day have an effect on tree growth, so there is a definite connection between trees and astronomy.  Jason, a local tree surgeon over at albanyorganics.com has long believed this and has written numerous research articles about the connection between the environment and astronomy.  As a hobby, he has built a telescope like those mentioned above on his roof.  It’s made by a company called Meade and runs around $3,600 for a cheap one.  It’s computerized, super easy to operate, and the quality is ridiculous (which I would expect for that kind of price).  When you get one of those though, be aware that they’re special requests, so they take a long time to ship.  I think it was 2-4 months if I’m not mistaken.  A special tripod mounts it to the roof.  I haven’t been up on the roof of his office lately, so I don’t have an exact photo of it, but this one is pretty close:

normal telescope

And laughably, we’re comparing it to pictures taken by Hubble that look like this:

amazing nebula

If you have a serious interest in astronomy or viewing the crazy things that happen in outer space, this (the normal person telescope) is exactly what you need.  Next time Haley’s Comet comes around, I’ll be 80 something years old, but I’ll have a great view 😉

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Next Challenge

How did our galaxy form? Our galaxy formed from a huge cloud of gas, w/ halo stars forming 1st and the disk stars forming later, after the gas settled into a spinning disk.

How are galaxies grouped together? Spirals collect in groups of a dozen or so. Ellipticals collect in groups of 100’s or thousands.

How do we measure the distances to galaxies? Parallax measurements that build on radar ranging in our solar system, using parallax and the relationship between luminosity, distance, and brightness to calibrate standard candles, and using white dwarf supernovae as standard candles at distances greater than 10 billion light years.

How do stars orbit in our galaxy?  Stars in the disk orbit in circles going in the same direction. Orbits of halo and bulge stars have random orientations.

How does the radius of the event horizon change when you add mass to a black hole?  Increases

How are neutron stars discovered? Beams of radiation from a rotating neutron star sweep through space like a lighthouse beam, making them appear to pulse. Observations of these pulses were the first evidence of neutron stars.

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Questions of the Week

A galaxy is moving away at 0.1 light years per year and is 1.4 billion light years away.  How long did it take to get there?  14 billion years.  Age = distance/velocity = 1.4/.01 = 14

According to conservation of angular momentum, what would happen if a star orbiting in a direction opposite the neutron star’s rotation fell onto the neutron star?  The neutron star’s rotation would slow down.

Are habitable planets likely?  Billions of stars have sizeable habitable zones, but we don’t yet know how many have terrestrial planets in those zones

Are Earth-like planets rare or common?  We don’t yet know b/c we are still trying to understand all the factors that make Earth suitable for life.

Based on the value of Hubble’s constant, how old is the universe? 12 to 20 billion years

Big Bang:  made 75% H, 25% He, stars made everything else

Black hole info:  It is hard to fall into a black hole because they are small compared to the size of the universe; they can be orbited, and they don’t suck you in.  Near the event horizon, time slows

down and tidal forces are very strong.  Some x-ray binaries contain compact objects too massive to be neutron stars, so they’re probably black holes.  There are very massive black holes in the

center of most galaxies.

Could there be life on Mars?  Evidence for liquid water in the past suggests that life was once possible on Mars

Could there be life on Europa or other Jovian moons?  Jovian moons are cold, but some show evidence for subsurface and other liquids

Could there be neutron stars that appear as pulsars to other civilizations on other planets but not to us?  Yes

Does dark matter really exist?  Either it exists or our understanding of gravity is wrong and must be revised.

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Solar Observation

Solar Observation

Date

Observation Time

Shadow Length

Solar Angle

9/22 12:55 PM 57.0 0.81
9/23 12:55 PM 57.5 0.81
9/24 12:55 PM 58.0 0.80
10/3 12:55 PM 62.0 0.77
10/13 12:55 PM 72.0 0.69
10/18 12:55 PM 89.0 0.59
10/22 12:55 PM 104.0 0.52
10/30 12:55 PM 101.0 0.54
11/4*  12:55 PM* 127.0 0.44
11/23 11:55 AM 133.5 0.42

* Daylight Savings Time requires that measurements be taken one hour earlier, but I did not know to measure at 11:55 AM.  The 11/4 measurement was taken exactly one hour later than it should have been, which may skew the data slightly.

Date vs Solar Angle

The most difficult part about making precise measurements was measuring the shadow at exactly 12:55 PM once a week.  It was also difficult to measure the shadow when Daylight Savings Time started because I was in class every day at 11:55.  My data could have been improved if I measured the shadow with a tape-measure instead of a ruler, and also if I did not have class at the time we are supposed to measure the shadow.

The solar angle is the elevation angle of the Sun.  The solar angle of the Sun seems to decrease as time passes from September toward November.  The position of Earth in our orbit of the Sun causes the Sun to be lower in the sky.  The solar angle of the Sun will continue to decrease until the winter solstice around December 22.  Then, the solar angle will begin to increase again.

The greater the angle of the Sun at mid-day, the longer the day will be.  The winter solstice is the shortest day of the year, and the angle of the Sun is the lowest it will be in the sky.

The higher the Sun is at mid-day, the warmer the day will be.  As the Sun’s height decreases, the weather becomes colder (moving us toward the winter).  The length of the day relates to the weather because the shorter the day becomes, the colder the day will be.  The shortest day of the year occurs in the middle of the winter, around December 22nd, when it is very cold outside.

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Moon Observation

Moon Observation

Date Time Observing Location Direction of Moon Angular Height of Moon Moon Phase
9/16 9:00 PM MACC E 60 degrees Full
9/17 8:53 PM MACC E 55 degrees Waning Gibbous
9/20 9:00 PM MACC E 45 degrees Third Quarter
9/23 9:10 PM MACC E 35 degrees Waning Crescent
9/28 8:58 PM MACC SE 30 degrees New
9/30 9:00 PM MACC SE 45 degrees Waxing Crescent
10/6 7:48 PM MACC SE 60 degrees First Quarter
10/9 9:00 PM MACC E 75 degrees Waxing Gibbous
10/12 9:00 PM MACC E 60 degrees Full
10/14 9:00 PM MACC E 60 degrees Full
10/21 8:52 PM MACC E 45 degrees Third Quarter

The first pattern I observed was the phase of the Moon.  When I began to observe the Moon, it was already half way through its cycle of phases.  I observed a Full Moon on September 9 at 9:00 PM.  I observed the Moon in the Waning Gibbous phase the next day at 8:53 PM.  On September 20 at 9:00 PM, I observed the Moon in the Third Quarter phase.  Each successive time I observed the Moon, the phase changed.  After seeing the New Moon, Waxing Crescent, First Quarter, and Waxing Gibbous phases, the Moon phase became full again.  This process occurred over the course of 27 days according to my observations.  The moon phases are supposed to change over the course of 27 ½ days, so my observations were pretty accurate.

The second pattern I observed was the direction of the Moon.  According to my observations, the Moon was located East in the sky from September 16 to September 23.  The Moon was located South-East in the sky from September 28 to October 6.  Finally, the Moon was located East in the sky from my next observation on October 9 to October 21.  Basically, the Moon was in the same two areas of the sky for the duration of my observing period of a little over a month.  I am not sure what can be drawn from these observations.

The third pattern I observed was the angular height of the Moon.  On September 16 at 9:00 PM, I observed that the Moon had an angular height of about 60 degrees.  The following day, September 17 at 8:53 PM, the Moon seemed to have a slightly smaller angular height of about 55 degrees.  The Moon’s angular height appeared to decrease from 55 degrees to around 30 degrees, occurring on September 28 at 8:58 PM.  From that day on, the Moon’s angular height appeared to increase again, maxing out at a height of around 75 degrees on October 9 at 9:00 PM.  From that day, the angular height of the Moon appeared to decrease again.  My last observation was on October 21 at 8:52 PM.  The angular height of the Moon appeared to be 45 degrees on that day.  From my observations, I learned that the angular height of the Moon changes from day to day.  The angular height of the Moon actually changes with the phase of the Moon.  The angular height should be greatest when there is a New Moon and least when there is a Full Moon.  Most of my observations were around 9:00 PM during the course of the 27 days, so I observed that the Moon was highest in the sky when there was a Waxing Gibbous.    Had I observed the Moon phases at their respective highest angular heights, I would have observed that the New Moon had the highest angular height.

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Check It

I ask you – why would we post this?  I answer – Figure it out genius 😉

Guess you’ll have to wait and see what the next post could be about.  I’ll give you a hint, it has something to do with the theory behind this movie.

 

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