Nature of the Universe
Complete explanation about Universe, Stars, Planets, Solar System
Learning Content
🌌 What is Barandum?
Universe= Everything that exists - stars, planets, sub-planets, gases, dust, energy, space, time is all together!
📊 Barand sizes
| Detail | Size | Memoir |
|---|---|---|
| age | 1380 million years(13.8 Billion Years) | 🎯13.8 B= "13 ah 8" |
| diameter | 93 billion light years | 🎯93 B LY |
| Galaxies | 200 billion+(2000 crore+) | 🎯200 B Galaxies |
| Constellations | 10²⁴(uncountable quantity) | 🎯 The beach is more than sand! |
🔥 Big Bang Theory
Who said that?Georges Lemaître - 1927
What happened?
- 🔴 Eruption from a single point 13.8 billion years ago!
- 🔴 Everything was contained in a small point before the explosion
- 🔴 Expanding after the explosion
- 🔴 Barandum is still expanding!
🎯 TNPSC Shortcut - "BIG BANG"
B- Beginning
I- Inflation
G- Georges Lemaître (inventor)
B- Billion years - 13.8 (age)
A- All matter
N- Not visible before
G- Growing still
📝 Important questions
Q:What is the age of the grandson?
A:13.8 billion years ✅
Q:Who proposed the big bang theory?
A:George Lemaître ✅
Q:What is the current status of Barandum?
A:Expanding
🌟 Galaxies
The galaxy= A collection of billions of galaxies + gas + dust + black holes
📊 Types of Galaxies
| Type | form | example | Memoir |
|---|---|---|---|
| Spiral cluster(Spiral) | 🌀 Spiral shape | Milky Way, Andromeda | "Where S is for Spiral, S is for Sun" |
| Elliptical cluster(Elliptical) | 🥚 Egg shape | M87, M49 | "E for Egg shape" |
| A disorderly mass(Irregular) | ❓ No form | Megalanic clouds | "I for Irregular" |
🌌 Milky Way Galaxy
🎯 Milky way important information
| Type | Spiral Galaxy |
| diameter | 1,00,000 light years(1 Lakh LY) |
| Constellations | 100 - 400 billion |
| Place of Sun | Orion Arm |
| Sun from the center | 26,000 light years |
| is in the center | Giant Black Hole (Sagittarius A*) |
🎯 TNPSC Shortcut - "MILKY"
M- Middle has Black Hole
I- 1 Lakh Light Years diameter
L- Lots of stars - 100-400 Billion
K- K = Orion Arm
Y- Years 26,000 LY from center
🔭 Neighboring galaxies
| Name | Distance | Special |
|---|---|---|
| Andromeda(Andromeda - M31) | 25 lakh light years | 🔴 coming towards us! Collision in 450 million years |
| Large Megalian Cloud(LMC) | 1.6 lakh light years | A companion galaxy |
| Small megalotonic cloud(SMC) | 2 lakh light years | A companion galaxy |
📝 Important questions
Q:What type of galaxy is the Milky Way?
A:Spiral Galaxy ✅
Q:In which part of the Milky Way is the Sun?
A:Orion Arm (Orion Arm) ✅
Q:What is at the center of the Milky Way?
A:Giant Black Hole (Sagittarius A*) ✅
☀️ Solar System
solar system= Sun + 8 Planets + Subplanets + Dwarf Planets + Asteroids + Comets
Age:460 Crore Years (4.6 Billion Years)
🎯 8 Planets – Sequential Remembrance Formula
"My Very Eager Mother Just Served Us Noodles"
Mercury -Venus-Earth-Mars-JJupiter -Saturn-Uranus -Neptune
In Tamil: "Buvisebhumivyasane"
Thuhis -Wlli -Flowermi -SecWow -VThursday -Sat-URhenus -NeBtune
📊 Planets Comparison Chart
| Planet | Type | satellites | Special | Memoir |
|---|---|---|---|---|
| Mercury | Rock | 0️⃣ | Very small, very fast | 🎯 "Wednesday = new + small" |
| Venus | Rock | 0️⃣ | Super hot, back spin | 🎯 "Silver = more heat" |
| Earth | Rock | 1️⃣ (Moon) | The only planet with life | 🎯 "Earth = Blue + Life" |
| Mars | Rock | 2️⃣ | The red planet, Olympus Mons | 🎯 "Mars = Purity (Red)" |
| Jupiter | gas | 95️⃣ | Big, big red dot | 🎯 "Jupiter = Vast" |
| Saturn | gas | 146️⃣ | Beautiful rings, floating in water | 🎯 "Saturn = King of Rings" |
| Uranus | Snow | 28️⃣ | Tilt and swivel (98°) | 🎯 "Uranus = Recumbent" |
| Neptune | Snow | 16️⃣ | Farthest, blue color | 🎯 "Neptune = Blue" |
🏆 Planetary Achievements
| achievement | Planet | Memory Trick |
|---|---|---|
| Biggest planet | Jupiter | "J = Jumbo" |
| The smallest planet | Mercury | "M = Mini" |
| Hottest planet | Venus | "V = Very Hot" |
| The darkest planet | Uranus | "U = Ultra Cold" |
| Very high satellite | Saturn - 146 | "S = More Satellites" |
| Highest mountain | Tuesday - Olympus Mons | "Mars = Mountain" |
| Non-satellite | Wednesday, Friday | "First 2 = Zero" |
📝 Important TNPSC Questions
Q:The largest planet in the solar system?
A:Thursday ✅
Q:Hottest planet?
A:Friday (although Mercury is near the Sun!) ✅
Q:Which is the red planet?
A:Tuesday ✅
Q:A planet with rings?
A:Shani (others have too, but Shani is clearly visible) ✅
☀️ The Sun
Surya Basic Information
| Type | Yellow Dwarf Star |
| age | 460 million years(4.6 Billion) |
| diameter | 13,92,000 km(109 times that of Earth) |
| surface temperature | 5,500°C |
| core temperature | 1,50,00,000°C(1.5 crore) |
| distance from earth | 15 crore km(1 AU) |
| The time it takes for the light to arrive | 8 minutes and 20 seconds |
| The main compound | Hydrogen (73%) + Helium (25%) |
🎯 Sun Shortcut - "SUN HEAT"
S- Surface temp 5,500°C
U- 1 AU = 15 crore km distance
N- Nuclear fusion is happening
H- Hydrogen 73%
E- Eight minutes 20 sec (to light)
A- Age 4.6 billion years
T- Temperature core 1.5 million°C
☀️ layers of the sun
| Layer | Explanation | remember |
|---|---|---|
| Core | A place where nuclear fusion takes place | "Core = Cooking place" |
| radiation zone | Energy travels as radiation | "Radiation Zone" |
| circulation zone | Heat is transmitted through circulation | "Convection Zone" |
| Photosphere | The region we see is - 5,500°C | "Photo = We will see" |
| Chromosphere | Red layer | "Chromo = Color" |
| Corona | Outer atmosphere, very hot | "Corona = Crown" |
⭐ Stars
📊 Types of constellations (by color)
| Color | temperature | example | remember |
|---|---|---|---|
| 🔵 Blue | Very hot (25,000°C+) | Rigal, Spica | "Blue = Burning hot" |
| ⚪ White | Heat (7,500-10,000°C) | Sirius, Vega | "White = Warm" |
| 🟡 Yellow | Medium (5,000-6,000°C) | the sun | "Yellow = Our Sun" |
| 🟠 Orange | Cold (3,500-5,000°C) | Arcturus | "Orange = Old star" |
| 🔴 Red | Very cold (2,500-3,500°C) | Betelgeuse | "Red = Rest" |
⭐ Major constellations
| Constellation | Special | TNPSC Tip |
|---|---|---|
| Sirius | Brightest constellation in the night sky | "Sirius = Seriously Bright" |
| Polaris | Pointing north | "Polaris = Pole Star" |
| Proxima Centauri | The closest galaxy to the Sun | "Proxima = Proximity" |
📝 TNPSC Questions
Q:Sun's surface temperature?
A:5,500°C ✅
Q:How long does sunlight take to reach earth?
A:8 minutes 20 seconds ✅
Q:Brightest constellation in the night sky?
A:Sirius ✅
Q:Nearest galaxy to the sun?
A:Proxima Centauri ✅
🎯 Barandum - Master Shortcut Chart
📊 Numbers memory table
| Detail | No | Memory Trick |
|---|---|---|
| Grand old age | 13.8 billion years | 🎯 Remember "13 is 8". |
| Age of the solar system | 4.6 billion years | 🎯 "4 Six" = 4.6 |
| Number of planets | 8 | 🎯 No Pluto! |
| Milky Way diameter | 1,00,000 light years | 🎯 "1 Lakh LY" |
| Sun-Earth distance | 15 crore km (1 AU) | 🎯 "15 = fifteen crores" |
| Time for sunshine | 8 minutes and 20 seconds | 🎯 Remember "8-20". |
| Solar surface heat | 5,500°C | 🎯 "5.5K" |
| Solar core heat | 1.5 crore°C | 🎯 "15 Million" |
🏆 First & Last - Quick Reference
| question | Answer |
|---|---|
| Biggest planet | Jupiter |
| The smallest planet | Mercury |
| Hottest planet | Venus⚠️ No Wednesday! |
| The darkest planet | Uranus |
| Near the sun | Mercury |
| away from the sun | Neptune |
| More satellite | Saturn - 146 |
| Non-satellite | Wednesday, Friday |
| Red planet | Mars |
| Blue planet | Earth / Neptune |
| Ring planet | Saturn |
| Bright star | Sirius |
| A nearby galaxy | Proxima Centauri |
| A nearby galaxy | Andromeda |
📝 Frequently asked MCQ
1.Who proposed the big bang theory?
a) Einstein b) Hubblec) George Lemaitre ✅D) Newton
2.The hottest planet in the solar system?
a) Wednesdayb) Silver ✅c) Earth d) Mars
3.What type of galaxy is the Milky Way?
a) Coiled mass ✅b) Elliptical cluster c) Irregular cluster d) Annular cluster
4.Sun's surface temperature?
a) 1,500°C b) 3,500°Cc) 5,500°C ✅d) 10,000°C
5.How long does sunlight take to reach earth?
a) 1 minuteb) 8 min 20 sec ✅c) 15 min d) 1 hr
6.Brightest constellation in the night sky?
a) Polar starb) Sirius ✅c) Vega d) Rigal
7.The closest galaxy to the sun?
a) Sirius b) Alpha Centauric) Proxima Centauri ✅d) Bernard
8.Which planets have no satellites?
a) Wednesday, Tuesdayb) Wednesday, Friday ✅c) Venus, Earth d) Mars, Jupiter
9.Approximate age of grandchild?
a) 4.6 billion yearsb) 13.8 billion years ✅c) 100 billion years d) 1 billion years
10.How many times larger is the sun than the earth?
a) 10 times b) 50 timesc) 109 times ✅d) 1000 times
🎯 Final Memory Trick - "UNIVERSE"
U- Universe age 13.8 Billion
N- Nearest star Proxima Centauri
I- Inner planets (Mercury, Venus, Earth, Mars) - Rocky
V- Venus is hottest (not Mercury!)
E- Eight planets only
R- Rings prominent in Saturn
S- Sirius is the brightest star
E- Eight minutes 20 sec (Sun to Earth light)
⚠️ Common Mistakes - Things to Avoid
❌ Mercury is the hottest planet → ✅FridayHottest planet
❌ Pluto is a planet → ✅ Plutodwarf planet(since 2006)
❌ More satellite for Jupiter → ✅to SaturnMost Satellite (146)
❌ Neptune is very dark → ✅UranusVery cold
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