Think of our Milky Way Galaxy as a flat circular disk of diameter 100,000 light-years. Suppose we are one of 1000 civilizations, randomly distributed through the disk, interested in communicating via radio waves. How far away in light years would the nearest such civilization be from us on average? Show your working. (Hint: Begin by calculating the area of the disk. Find the area of one of a 1,000 squares. Consider the separation of the centres of two adjacent squares.)

Q: A newly discovered orange dwarf star has a surface temperature of approximately 5185 K. How far…

A: If we know the star's luminosity L, then the habitable zone distances range from  0.95LL0 to…

Q: The Apollo program (not the lunar missions with astronauts) being conducted at the Apache Point…

A: The spped of the ligth v=3×105m/ss=384,472km

Q: 1.The world population is growing at a consistent rate of 1.05% every year. If the present…

A:

Q: As discussed in class, the moon is receding from the Earth due to tides at a rate of ~4 cm/year.…

A:

Q: Which of the following is least reasonable regarding the difficulty in contacting extraterrestrial…

A: "The spacecraft that NASA sent to Proxima Centauri a few years ago should be approaching its target…

Q: If you detected radio signals with an average wavelength of 37 cm and suspected that they came fro

A: Given: Average wavelength is  λa=37cm=0.37m  Earth's orbital velocity is v=30km/s v=30*103 m/s…

Q: Suppose that Earth grew to its present size in 11 million years from particles averaging 190 g each.…

A: As given the present size of the earth is grown through 11 million years from  particles of mass m…

Q: Th Course: SUNO - 2020 FALL - Ma x W HW 3 - SPHY 213N General Phys X W HW 3- SPHY 213N General Physi…

A: Since we only answer up to 3 sub-parts, we’ll answer the first 3. Please resubmit the question and…

Q: Using our example from the previous unit, let's try to determine the Hubble time for this example…

A: Solution     Given dataSpeed v=4000km/sDistance d=20Mpcwhat would the age of that universe be in…

Q: Suppose that stars were born at random times over the last 10e10 years. The rate of star formation…

A:

Q: Suppose there are 9000.0 civilizations broadcasting radio signals in the Milky Way Galaxy at the…

A: According to the given information, there are 8x1011 stars in the Milky way galaxy and there is one…

Q: If the speed of light is given as  299,792,458 meters per second and the wavelength is 478 nm.  what…

A: Given velocity of light c = 299,792,458 m/s wavelength of light λ= 478 nm we have to calculate the…

Q: 1. The biceps muscle exerts a muscle force of 1000N on the forearm, as per the picture below. The…

A:

Q: Scientists agree that the age of the universe is about 4 billion years old, does the age of the rock…

A: Given:  Half life of radioactive potassium = 1.25 billion years Ratio of stable argon to radioactive…

Q: random times over the last 1010 years. The rate of star formation is simply the number of stars…

A: Number of stars in our milky Way galaxy is  N=9×1010 Time taken in the formation of a plane

Q: Problem 1: For each picture shown, draw a free body diagram for the object, calculate the net force…

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Q: Problem 2 A4 ohm, 8 ohm, and 12 ohm resistor are connected in series to a 24 V battery. 'Find the…

A: GIven : V=24 V R1=4Ω R2=8Ω R3=12Ω

Q: Suppose there are 12000.0 civil actions broadcasting radio signals in the Milky Way Galaxy at the…

A: Given that There are 12000 civil actions broadcasting radio signals in the milky way galaxy at the…

Q: Suppose you gathered a ball of interstellar gas that was equal to the size of the Earth (a radius of…

A:

Q: Let's say that the number density of galaxies in the universe is, on average, 3 × 10–68 galaxies/m3.…

A: Given :number density of galaxies, n = 3 × 10–68 galaxies/m3            Observable distance by…

Q: Question 3 Small (nano-meter scale) identical particles are found suspended in a liquid like those…

A: Given, h1=4mm h2=8mm h3=9mm

Q: Voyager 1 is one of the most distant and fastest moving human made objects as measured from Earth.…

A: Since 1977 the number of years passed are 2021 – 1977 years = 44 years.

Q: How often (in years) does a planetary system form in our galaxy?

A: Number of stars in our galaxy = 3 x 1011 stars time to consider = 1010 years rate of star formation…

Q: Suppose that stars were born at random times over the last 1010 years. The rate of star formation is…

A: Given that, The total number of stars in the Milky way is N=8×1011 And the stars were born at random…

Q: What is the wavelength (in kilometers) of the 56,500-Hz radio wave used clocks and wristwatches?…

A:

Q: The number density of air in a child's balloon is roughly the same as sea level air, 1019…

A: Number of particles in the balloon is, N=nVN=n×43πR3

Q: 1. Explain what has happened to the number of elements in the universe over time (beginning with the…

A: The entire cosmic system of matter and energy, of which Earth and its inhabitants are a part.…

Q: If a galaxy is 9.3 Mpc away from Earth and recedes at 508 km/s, what is H, (in km/s/Mpc)? |km/s/Mpc…

A: velocity, v=508 km/s distance, d=9.3 Mpc=9.3×3.086×1019 Km=28.7×1019 Km. Hubble constant,…

Q: Suppose there are l0,000 civilizations broadcasting radio signals in the Milky Way GaIaxy right now.…

A: Given :     No. of stars in the galaxy = 500 billion = 500 x 109 stars     Case-1    No. of…

Q: Suppose your shortwave radio has a frequency of 300 MHz. If the speed of light is 300,000,000 m/s,…

A:

Q: 4a. After reading the articles, what do you think overall about whether we should search for life on…

A: 4a. I think we should definitely search for life on other planets. We should also work towards…

Q: Our Solar System completes one orbit every 200 million years around the Galactic Center. Our Sun is…

A: The number of revolutions of the solar system around the galactic center will be equal to the number…

Q: Most of the stars we can see with the unaided eye in our night sky are hundreds or even thousands of…

A: The question is asking us to comment on the feasibility and practicality of visiting, communicating…

Q: Consider three periods in the history of the Universe: one million years after the Big Bang (age = 1…

A: In early times, the Universe was expanding at a rapid pace. Then, the rate of expansion of the…

Q: 8. The human eye has an angular resolution of about 1' (one arcminute - recall there are 60…

A: original angular resolution, θ=1'=2.91×10-4 radian 1°=π180 radian , 1°=60', 1'=π180×60 radian…

Q: Imagine that in the future, scientists plan on colonizing planets that orbit other stars. Based on…

A: SOlution:

Q: You record the spectrum of a distant star using a telescope on the ground on Earth. Upon analysing…

A:

Q: If you detected radio signals with an average wavelength of 68 cm and suspected that they came from…

A: Given data: Wavelength of radio signal, λ=68 cm. Orbital speed, v=30 km/s.

Q: In the deep space between galaxies, the density of atoms is 1 million atoms per m3 (i.e. there are 1…

A: Given: Density of an atom = 1 million atom in a m3. Temperature = 3 K

Q: Suppose you want to observe the molecular gas in a galaxy with redshift z using the rotational…

A: Suppose you want to observe the molecular gas in a galaxy with redshift z using the rotational…

Q: Let's say that the number density of galaxies in the universe is, on average, 3 × 10–68 galaxies/m3.…

A:

Q: D

A: Solution: The four model are as follows, Critical Accelerating Coasting Recollapsing The present…

Q: Imagine that we discovered a new planet that has the potential to support life. This planet has…

A: Plants to live undergo the process of photosynthesis. To undergo photosynthesis, plants need water,…

Q: If the universe had a density equal to its estimated critical density of 9= 10-30 g/cm3, and if it…

A: Given Critical density ρc =  9×10-30 g/cm3 Mass  (M)                 = 2.0 × 1030 kg

Q: To figure out how many light years a signal has traveled we need to know how long since the signal…

A: The time taken  till now from the broadcast is 95 years.   ( the distance traveled by light in one…

Q: Water is life. Nothing survives without water. Water is abundant everywhere. Now, we said before…

A: We can separate hydrogen from water by process of electrolysis of water . When current is passed…

Special Relativity

The theory of special relativity discusses how space and time are related to objects traveling along a straight line at a constant speed. Simply stated, as an object reaches the speed of light, its mass becomes infinite and it is unable to move faster than light. This interstellar speed limit has been the topic of much debate in astronomy, and also in science fiction when people consider how to fly over large distances.