Have you ever heard someone say that Earth travels around the Sun in a perfect circle? Well, that's not actually true. Most of us picture Earth orbiting the Sun like a marble going around the center of a track. But in reality, Earth's orbit is slightly stretched out into an oval shape called an ellipse. That means there are times during the year when we're a little closer to the Sun and times when we're a little farther away.
I'm Matteo Andres, and this is Discovery Deep Dive.
On July 6th, Earth reached its farthest point from the Sun this year, a spot astronomers call aphelion. At that moment, we were about 94.5 million miles away from our sun. Compare that to early January when Earth is at perihelion, its closest point to the Sun, at about 91.4 million miles away.
Now, if you're thinking, "Wait, shouldn't it be cooler when we're farther away?" not really. The difference is only around 1-3%, so you won't notice the Sun looking any smaller or dimmer, than it has before.
But here's something you might notice here on Earth. The Moon's orbit is also an ellipse. When the Moon swings a little closer to the Earth, its gravity will pull more strongly on its oceans. Combined with the Sun's gravity, this can create higher-than-normal tides, known as perigean tides. The Moon will be at perigee on July 13th with a new moon being on July 14th! If you can, go to the shore this month and see just how high the tides will be.
It's a fascinating reminder that the motions of objects hundreds of thousands, or even millions of miles away, aren't just happening out in space. They can have real, measurable effects right here on Earth.
