blackbodies - 2024 PLAYTIME

Question

Radiation from stars may be characterized by the Stefan–Boltzmann law by assuming the star is one of these objects. For 10 points each:

[10m] Name these ideal, diffuse emitters. These objects have an energy spectrum given by the Planck distribution.

ANSWER: blackbodies [or black-body]

[10h] This satellite’s Differential Microwave Radiometers confirmed that the Cosmic Microwave Background is a near-perfect blackbody with faint anisotropies. This first satellite to study the CMBR in depth was succeeded by WMAP.

ANSWER: COBE [or the Cosmic Background Explorer or Explorer 66]

[10e] The Stefan–Boltzmann law relates the radiant exitance of an object to the fourth power of this quantity, which can be used to define an “effective” form of it for stars. The CMB acts as a blackbody with a value of about 2.7 Kelvin for this quantity.

ANSWER: temperature [accept effective temperature]

<JC, Physics - Astronomy>

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Summary


2025 PLAYTIME @ CWRU	12/10/2024	Y	5	22.00	100%	100%	20%
2025 PLAYTIME @ Claremont	12/10/2024	Y	5	20.00	100%	100%	0%
2025 PLAYTIME @ Florida	12/10/2024	Y	2	25.00	100%	100%	50%
2025 PLAYTIME @ Florida	12/10/2024	Y	1	20.00	100%	100%	0%
2024 PLAYTIME @ Harvard	04/26/2025	Y	4	17.50	100%	75%	0%
2024 PLAYTIME @ JHU	10/26/2024	Y	8	12.50	88%	38%	0%
2025 PLAYTIME @ Northwest	12/10/2024	Y	4	15.00	75%	75%	0%
2025 PLAYTIME Online	04/26/2025	Y	9	24.44	100%	100%	44%
2025 PLAYTIME @ Sheffield	12/10/2024	Y	6	20.00	83%	100%	17%
2025 PLAYTIME @ Sheffield	12/10/2024	Y	1	30.00	100%	100%	100%
2024 PLAYTIME @ UBC	10/05/2024	Y	8	18.75	88%	88%	13%
2024 PLAYTIME @ Virginia Tech	07/11/2025	Y	3	26.67	100%	100%	67%
2024 PLAYTIME @ WashU	10/12/2024	Y	6	21.67	100%	100%	17%

Data


Pittsburgh	Michigan A	10	0	10	20
Ohio State A	Michigan C	10	0	10	20
Ohio State B	Michigan B	10	0	10	20
Michigan D	Ohio State C	10	0	10	20
Ohio State D	Oberlin	10	10	10	30
Caltech	UCLA B	10	0	10	20
UCLA A	Claremont A	10	0	10	20
Claremont B	UCSD	10	0	10	20
P.C.‚ Daniel‚ Michel‚ and Jason B	Art of Premature Signaling	10	0	10	20
girl 15 whale i mean they	UCSB	10	0	10	20
Project2025BC: Make Assyria Great Again	Billy's Bastion	10	10	10	30
Edwin Laundrorat's Long-Lost Man Unclothès Rat Degrosses	Keeping Up With the Cardassians	10	0	10	20
Qin Shi Huang's Immortality Poison	Too much from you lately	10	0	10	20
Belmont	Lexington	0	0	10	10
RIT	Brown	10	0	10	20
Harvard	BU	10	0	10	20
MIT	Brandeis	10	0	10	20
George Washington	Maryland A	0	0	10	10
Johns Hopkins A	Haverford A	10	0	10	20
Haverford B	NYU B	0	0	10	10
Catholic University of America	Johns Hopkins B	0	0	10	10
Maryland B	NYU A	10	0	10	20
Arizona State University A	Carleton	10	0	10	20
Alberta	Arizona State University B	10	0	10	20
UW A	UW B	10	0	10	20
South Dakota School of Mines	Washington Connections	0	0	0	0
CWRU	George Mason A	0	0	0	0
Georgetown	George Mason B	0	0	10	10
NYU C	George Mason C	10	0	10	20
Imperial A.	Imperial B	10	10	10	30
Birmingham	Manchester	10	0	0	10
Sheffield A	Edinburgh	10	10	10	30
Sheffield B	Cambridge	10	0	10	20
LSE	Warwick A	10	0	10	20
Warwick B	Lancaster	10	0	10	20
Warwick C	Sheffield C	10	0	10	20
Waterloo C	Guelph	10	10	10	30
Mac A	McGill B	10	0	10	20
Ottawa A	UBC	10	0	0	10
Waterloo B	Toronto A	10	0	10	20
Toronto Metropolitan	Toronto B	0	0	10	10
Toronto C	Simon Fraser	10	0	10	20
Toronto D	Toronto E	10	0	10	20
McGill A	Waterloo A	10	0	10	20
Adrianne Lenker 4 Nobel Lit Prize 2K65	4 quizbowl pros go Virginia on North Carolina	10	10	10	30
Ashurbanipal’s Drag Race	Master and Margaritaville	10	10	10	30
Even in Blacksburg There I Am	Somehow Paula Deen Returned	10	0	10	20
WashU Squirtle	Chicago B	10	0	10	20
Chicago A	Illinois A	10	0	10	20
Illinois B	Illinois C	10	0	10	20
Truman State	Iowa State	10	0	10	20
WashU Bulbasaur	Missouri	10	10	10	30
WashU Charmander	SIUE	10	0	10	20
Notre Dame + Epic Games	2 Italians, 2 Poles, All Noles	10	0	10	20
Four Generalists in Search of a Power	Auburn 2026	10	10	10	30
Quatumvirate	Goober Gang	10	0	10	20
Mahjonng Masters	Gruh	10	10	10	30
Monsieur Hulot's Academic Team	Mike Dukakis Tank Battalion	10	10	10	30
Free Agents 1	Trip-Hop Quizzer Tricky	10	10	10	30
evil women enjoyers	Egypt Airlines Haters	10	0	10	20
mongeese	MSJ	10	0	10	20
Illinois Orange	we need new names	10	0	10	20