Northern Lights - what are they?

2024/12/19

What in the World

People

Caroline Steele

Hannah Gelbart

Hugo Korhonen

Topics

Hannah Gelbart: 本期节目探讨北极光和南极光的成因、观测频率增加的原因以及最佳观测地点，并邀请了BBC科学节目主持人Caroline Steele和芬兰摄影师Hugo Korhonen进行讲解。 Caroline Steele: 北极光是由太阳释放的带电粒子（太阳风）与地球大气层中的原子碰撞产生的。太阳风通常被地球磁场阻挡，但在日冕物质抛射等事件发生时，部分带电粒子会进入地球两极，与氧原子和氮原子碰撞，分别发出绿色和蓝紫色光。北极光的声音现象也得到了科学证实，在特定条件下，暖空气层与极光相互作用会产生类似白噪声的噼啪声。近年来，北极光出现频率增加的原因有两个：一是太阳活动周期，目前正处于太阳活动高峰期；二是智能手机普及和社交媒体传播，使得更多人能够观测和分享北极光现象。观测北极光的最佳地点靠近北极圈，如冰岛、挪威和苏格兰等地；南极光则在南极洲及其附近地区可见。观测时应远离光污染，选择晴朗无云的夜晚，避免满月。最佳观测时间为北半球的11月至次年3月，南半球的3月至9月。 Hugo Korhonen: 作为一名芬兰摄影师，他分享了拍摄北极光的经验，建议使用手机夜间模式或专业相机，并使用三脚架以获得更长的曝光时间。他还建议调整ISO、快门速度和光圈等参数，并强调了拍摄时构图和故事性表达的重要性。 Caroline Steele: 极光对地球的影响主要体现在对无线电通讯和电力系统的干扰，但通常不会造成严重后果。极端情况下，强烈的极光活动可能导致电力系统出现电涌，但这种情况非常罕见。地球磁场的存在对于保护地球生命至关重要。

Deep Dive

Key Insights

What causes the Northern Lights?

The Northern Lights are caused by charged particles from the sun colliding with atoms in Earth's atmosphere, particularly oxygen and nitrogen, which emit light as a result.

Why are the Northern Lights different colors?

The color depends on the type of atom the charged particles collide with. Oxygen atoms produce green light, while nitrogen atoms produce blue, purple, or pink light.

Why are people seeing more Northern Lights in 2024?

The increase is due to a solar maximum, where the sun is more active, leading to more coronal mass ejections. Additionally, more people are sharing sightings due to smartphones and social media.

Where are the best places to see the Northern Lights?

Ideal locations include areas near the Arctic Circle, such as Iceland, Norway, and Scotland. For the Southern Lights, places like Antarctica, South Africa, New Zealand, and Tasmania are best.

What is the best time of year to see the Northern Lights?

In the northern hemisphere, the best time is from November to March, when nights are longer and darker. In the southern hemisphere, it’s from March to September.

Can you hear the Northern Lights?

Scientists have recently discovered that 5% of the time, the Northern Lights produce a crackling sound due to static charge interacting with a warm air layer near the Earth's surface.

What are some tips for photographing the Northern Lights?

Use a tripod for longer exposure times, adjust ISO, shutter speed, and aperture settings, and consider the story you want to tell with the photograph.

Are there any negative effects of the Northern Lights?

While the Northern Lights can interfere with radio communication and GPS, they rarely cause significant issues. Extreme cases can disrupt power grids, but such events are rare.

Chapters

This chapter explores the Northern Lights, describing their appearance, the science behind their creation through charged particles from the sun colliding with atoms in Earth's atmosphere, and the reasons for their varied colors. It also touches upon the misconception of their sounds.

The Northern Lights are ribbons of light in the sky, often green or purple.
They are caused by charged particles from the sun colliding with atoms in Earth's atmosphere.
Different colors result from collisions with different atoms (oxygen for green, nitrogen for blue/purple).

Shownotes Transcript

Even if you haven’t seen them in person, you might be familiar with images of the Northern Lights - dark skies with moving ribbons of green and purple. But what actually are they? And why do we seem to be seeing more of them in 2024?

BBC science presenter Caroline Steele answers loads of questions about the Northern Lights, like why are they different colours and when and where are the best times to see them? We also chat about the Southern Lights and ask why don’t people talk about them as much?

And 21 year old photographer Hugo Korhonen from Finland tell us what it’s like to see the Northern Lights in person and how you can take the best photos of them.

Instagram: @bbcwhatintheworld Email: [email protected] WhatsApp: +44 0330 12 33 22 6 Presenter: Hannah Gelbart Producers: Julia Ross-Roy and Maria Clara Montoya Video Journalist: Adam Chowdhury Editor: Verity Wilde

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