pale blue dot
On October 16, 2017, for the first time ever in history, scientists were able to detect gravitational waves from two neutron stars’ merger. Carl Sagan’s famous quote says “The nitrogen in our DNA, the calcium in our teeth, the iron in our blood, the carbon in our apple pies were made in the interiors of collapsing …
Continue reading “LIGO detects gravitational waves from neutron star merger”
Why do we see only one side of the Moon? You have probably heard references being made to the “dark side” of the Moon – there’s even a Pink Floyd album with that name. But, in fact, there’s no “dark side” of the moon. Because our satellite is not illuminated by the Earth, it is illuminated by …
Continue reading “Why do we see only one side of the Moon? [Tidal locking explained]”
We see images and videos from the International Space Station (ISS) where astronauts float in space freely. That’s because they’re in space, so there is no gravitational force of Earth there, right? Wrong. The International Space Station is in Low Earth Orbit (see notes 1) with an altitude of between 330 and 435 km (205 …
Continue reading “Why do astronauts float in space? [Microgravity explained]”
What if we could make a spaceship that is capable of leaving the solar system at the speed of light? How much time would it take to enter interstellar space? Our Solar system is big, and vast, despite it being really small compared to our galaxy, not to mention the complete universe. To put this …
In 240 BC, the Greek astronomer, geographer, mathematician, music theorist, and librarian Eratosthenes of Cyrene (c. 276 BC – c. 195/194 BC) calculated the circumference of the Earth without even leaving Egypt. Here’s how:
A beautiful video, once again, from Michael Stevens, titled “How Earth Moves”. Michael explains many concepts, including “sub-solar point”, “sidereal day vs solar day”, or “how Earth moves in the space” etc, and he is doing it in a very simplified manner. Enjoy!
Can we, humans, be one of the few (or the only) civilizations in the Universe that surpassed the so-called “great barrier”? Are we the first?
“Your life on Earth” is a nice interactive webpage presented by the BBC – The British Broadcasting Corporation: how you and the world have changed since you were born? You’re simply entering your birth date, gender, and height; selecting units (metric or imperial/US), and then watching how our planet (and you) has changed in your …
The Earth would NOT look like this without water. Please stop sharing this nonsense. Here are some numbers: the Earth has a diameter of about 12,735 kilometers (on average). The highest point on Earth is the top of Mount Everest, at 8,848 meters (29,029 feet). The deepest point on Earth is the Mariana Trench, at …
Continue reading “No! The Earth Would NOT Look Like This Without Water”
It’s a well-known fact that a feather will fall slower than a bowling ball due to air resistance. However, what happens if you remove the air and drop both objects in a vacuum? Surprisingly, they will fall at the exact same speed. This might seem counterintuitive, but it’s actually a result of a fundamental principle …
Continue reading “Bowling ball and feather fall in a vacuum at the exact same speed [Here’s why]”
