Haben Sie Astronomie Olimpiad in Deutchland?

kill'm · Gast

Haben Sie Astronomie Olimpiad? Ich suche fur astronomie olimpiad aus Welt. Ich habe alle Polnische Astronomie Olimpiad.

kill'm
Kraków
Polen
P.S.
I'm very sory for making so many mistakes. Ich spreache Deutch schleht. Would it be very inpolite if i write here in englisch?

dermarkus · Administrator Anmeldungsdatum: 12.01.2006 Beiträge: 14788

,
As I most certainly assume, our Polish is much worse than your German, so it should only be fair to use English smile

Maybe it would help if you explain a little more what you mean by "Astronomie-Olympiade".

Is this a national physics contest on astronomy, and are you looking for a collection of exercises from all the past years?

Or is this a Polish journal on astronomy, of which you have all the issues that have appeared so far, and which might exist in other languages, too?

Cheers, Markus

para · Moderator Anmeldungsdatum: 02.10.2004 Beiträge: 2874 Wohnort: Dresden

Since it's probably the most effective way to communicate English I wouldn't call it impolite in any way. I'm glad you found your way to this board.
I would agree to dermarkus, that it would be useful to specify more precisely, what you mean by "astronomie olimpiad". If you should mean the International Astronomy Olympiad I'm pretty sure that Germany doesn't take part in that (yet), so that there's no national selection procedure or competition as for the IPhO, IChO, IBO and so on.
I'm not sure about the existence of any specific national astronomy competition in Germany. But I guess if there is something like that, one should be able to find it easily if via google since such competitions usually depend on good publicity to reach as many participants as possible.

Gast

hello

kill'm · Anmeldungsdatum: 05.02.2006 Beiträge: 4

^it was me. I don't know why i wasn't logged in.

dermarkus · Administrator Anmeldungsdatum: 12.01.2006 Beiträge: 14788

that looks like fun! So let's start collecting exercises on astronomy here, e.g. from German IPhO.

I have found one so far, which is exercise 4 from the first round 2004:

http://docs.sfz-bw.de/ipho/IPhO2004-1.pdf , page 2, Aufgabe 4

I translate it as:
----------------------------------------------
Density of a planet

Recently, in a far distant astral system a new planet was discovered, which is very dense, sphere-shaped and does not have an atmosphere. This planet rotates around his axis in 60 minutes.
Estimate the minimal density of this planet.
----------------------------------------------

On the same page I found names of persons organizing the German IPhO competitions. I think they might very well be delighted to exchange some ideas and exercises with you. One of them, Gunnar Friege, has the following homepage:
http://www.ipn.uni-kiel.de/persons/friege.htm

Cheers, Markus

dermarkus · Administrator Anmeldungsdatum: 12.01.2006 Beiträge: 14788

dermarkus · Administrator Anmeldungsdatum: 12.01.2006 Beiträge: 14788

Hi Rafał,

Another problem (first round 1997) from the IPhO homepage:

http://www.ipn.uni-kiel.de/projekte/ipho/start.htm

--------------------------------------------

Raumschiff (1. Runde 1997)

Ein Raumschiff, das auf der Erdbahn um die Sonne kreist, wird so abgebremst, dass es relativ zur Sonne ruht. Wie lange dauert es, bis es mit der Sonne kollidiert?

Man betrachte die Sonne als Massenpunkt und die Erdbahn als Kreis! Die Aufgabe lässt sich ohne Differentialrechnung lösen!

-----------------------------------------------
my translation is:

spacecraft (IPhO first round 1997)

A spacecraft circling the sun on the earth's orbit around the sun is decelerated such that its velocity with respect to the sun is zero. How long does it take until it collides with the sun?

The sun is to be considered as a point mass and the earth's orbit around the sun as a circle! This problem can be solved without a differential equation!
-------------------------------------------------

Cheers, Markus

kill'm · Anmeldungsdatum: 05.02.2006 Beiträge: 4

exercises from Poland:
orginal version
Jedna z hipotez próbójąca tłumaczyć niektore zaburzenia w ruchu planet zewnętrznych jak również anomalie w okresach pulsarów zaklada że słońce wchodziw skład ukladu podwójnego, którego drugim składnikiem jest gwiazda nadająca Słońcu przyspieszenie a=6*10^-9 m/s^2
jaką temperaturę efektywną mialaby ta gwiazda, gdyby założyć, że jej masawynosi M=1,4 mas slońca, promień 12km, a jej obserwowana wielkość gwiazdowa wyrażałaby sie liczbą większą od 18? Czy gwiazdy o takich parametrach fizycznych mogą obecnie istnieć?

my translation:
There is a theory that explain perturbation in external planets movements and anomalys in pulsars periods. It says that Sun is part of the double system. It' second component accelerate Sun (a=6*10^-9 m/s^2)
What is an effective temperature of second component. You know that its mass is M=1,4 Ms (Ms-Sun mass)
radius =12km its apparent magnitude is a number <18mag. Is this theory correct? Is existance of this star possible nowadays?

I'll write something in the evening after the school.
Cheers, kill'm

Gast

I'm sorry for being late i had something like conjunctivitis an i couldn't use a computer.
exercise written below was one of four ex. on final selection on Polish AO in '89 :

granted that
all energy radiated by a Sun comes from thermonuclear reaction H -> He

estimate (calculate):
A) stream of neutrinoes near Sun
B) what part of Hydrogen was changed into helium, If the Sun radiation rate is constant and it radiate ror 5 bln. years.
C) How large is a capacity in the Sun in wchich in 1 second take place 1 termonuclear reaction H->He
You have:
Sun constant: S=1.36*10^3 J*m^2*s^-1
Astronomical unit: 1AU=149,6*10^6 km
Sun radius: R=6,96*10^5 km
Sun mass: M=1,99*10^30 kg
hydrogen mass: m1=1,008u
helium mass: m2=4,003u
Avogadro number N=6,022*10^23 molecules/mol

Try to solve it. i think that this one is easy. If you didn't understand something it mean that I made a mistake during translation. Don't hesitate to ask I'll to explain it in other word's.

kill'm

dermarkus · Administrator Anmeldungsdatum: 12.01.2006 Beiträge: 14788

Hi,

I have found some more German IPhO exercises on astronomy:

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first round 1985:

Wenn man die Bahn der Sonne gegenüber dem Fixsternhimmel betrachtet, stellt man kleine monatliche Schwankungen von etwa 12.8'' fest. Der Abstand Erde - Sonne beträgt 1.5*10^11 m, der Abstand Erde - Mond 3.8*10^8 m.
Bestimmen Sie aus diesen Angaben das Verhältnis der Massen von Erde und Mond.

my translation:

When one observes the path of the sun relative to the heaven of fixed stars, one observes small monthly fluctuations of about 12.8''. The distance between earth and sun is 1.5*10^11 m, the distance between earth and moon 3.8*10^8 m.
Determine from this information the ratio of the masses of earth and moon.

-------------------------------------------------------------------------

first round 1990:

Sie schauen am Abend ihres Geburtstages gegen 21 Uhr zum Sternenhimmel und sehen im Osten einen hellen Stern aufgehen. An ihrem nächsten Geburtstag suchen Sie Ihren Stern wieder, aber er lässt sie fast bis Mitternacht warten. Offenbar war es kein Stern, sondern ein Planet.
Wie weit ist er ungefähr von der Sonne entfernt?
Um welchen Planeten handelt es sich also?
Begründen Sie Ihre Antwort!

my translation:

On the evening of your birthday around 9 pm you look up to the sky of stars and you observe a bright star rising on the horizon in the east. On your next birthday, you search for your star again, but the star lets you wait almost until midnight. Apparently, this was not a star, but a planet.
What is its approximate distance from the sun?
So which planet are we talking about?
Give reasons for your answer!

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third round 1990:

Die Rotationsfrequenz der Erde wird durch die von der Sonne herrührenden Gezeiten verlangsamt (und außerdem natürlich durch die Mondgezeiten, die hier jedoch nicht betrachtet werden sollen). Irgendwann wird der Tag so lang sein wie jetzt das Jahr.
Um wieviel wird sich dann der Bahnradius der Erde verändert haben?
Realitätsferne Annahmen: Die Erde sei eine homogene Kugel, ihre Bahn ein Kreis, und den Mond soll es nicht geben.
Erdradius R=6370 km, Radius der Erdbahn a=1.49*10^11 m
Trägheitsmoment einer Kugel um eine Mittelpunktsachse: J=(2/5)mr^2

my translation:

The rotation frequency of the earth is being slowed down by the tidal forces caused by the sun (and of course by the tidal forces caused by the moon, but these shall not be considered here). At some time, the day will be as long as a year is now.
By how much will the radius of the earth's orbit around the sun have changed then?
Unrealistic assumptions: Assume that the earth is a homogeneous sphere, that its orbit is a circle, and that the moon does not exist.
Radius of the earth R=6370 km, radius of the earth's orbit a=1.49*10^11 m, moment of inertia of a sphere around an axis through its center: J=(2/5)mr^2

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first round 1992

Ein kleiner Mond mit der Masse m und dem Radius a umkreist einen Planeten mit der Masse M, wobei er ihm stets dieselbe Seite zukehrt.
Bei welchem Mondradius r werden Steine, die auf der Mondoberfläche liegen, angehoben?

my translation:

A small moon with mass m and radius a circles around a planet with mass M, while facing it always with the same side.
At which moon radius r will rocks that lie on the moon surface be lifted?

----------------------------

first round 1990:

Bestimmen sie die Größe der Gravitationsrotverschiebung für ein Photon mit Wellenlänge lambda=500 nm, das von der Sonne zur Erde fliegt.

my translation:

Determine the size of the gravitational red shift for a photon with wavelength lambda = 500 nm that flies from the sun to the earth.

---------------------

Cheers, Markus

dermarkus · Administrator Anmeldungsdatum: 12.01.2006 Beiträge: 14788

Hi,

I have the impression that many exercises that you have in Poland use a richer variety of astrophysics knowledge than the German IPhO exercises I found.

My answers are:

1) Assuming a "number >18mag" instead of a "number <18mag" because of "liczbą większą od 18" in the Polish original, I obtain that:

This theory is consistent with a neutron star with an effective temperature of less than 900 K.
The given rounded value for its mass m=1,4 Ms can be consistent with a mass bigger than the Chandrasekhar mass (1,44 Ms) because of the rounding uncertainty.
A neutron star with these physical parameters cannot exist nowadays, because the lifetime of the radiating star that it was plus the time the neutron star would need to cool down to 900 K is longer than the lifetime of the universe.

2) I assume the unit of the sun constant to be W/m^2=J*m^-2*s^-1 (and not J*m^2*s^-1).
a) neutrino flux near the sun = 3*10^19 m^-2*s^-1
b) 5 %
c) If I assume the "capacity" to be the size of a volume element, then this volume is 0.02 mm^3 if I assume a homogeneous distribution. As the reaction takes place only in the center region, and the density there is higher, the volume element there is much smaller. I roughly estimate it to be of the order of 10^-6 mm^3.

Cheers, Markus

kill'm · Anmeldungsdatum: 05.02.2006 Beiträge: 4

Hi,

I was on the Camp so I can't write. your's exercises wasn't very difficult more than half of students did them but it was something diffrent then Polish OA. thank You.

dermarkus · Administrator Anmeldungsdatum: 12.01.2006 Beiträge: 14788

Hi,

I am happy that the IPhO exercises I found helped you a little.

I now see that the official solution you give is correct. I indeed forgot a factor of 4 pi in one place and made a small rounding error.

So now, using:

Ms = 1.99*10^30 kg
G = 6.67*10^-11 m^3/(kg*s^2)
\sigma = 5.67*10^-8 W/(m^2*K^4)
magnitude of sun: m_s=-26.74
brightness of the sun b_s = 1360 W/m^2
radius of neutron star r_2 = 12 km

I have:

the distance of the neutron star from the sun d:

the brightness of the neutron star b_2 from the Pogson equation:

the radiation intensity of the neutron star P_2

I obtain for the temperature T_2 of the neutron star

and therefore

Gast

Hi,

dermarkus · Administrator Anmeldungsdatum: 12.01.2006 Beiträge: 14788

Very nice joke!