2024 年 4 月 23 日
飞机凝结尾的X形影子
影像提供与版权: Fatih Ekmen
说明：这朵云上的庞大X形是怎么来的？它是飞机凝结尾受到下方阳光照射所投射的影子。当飞机航行时，引擎排放的潮湿废气，可在地球冰寒的高层大气凝结成水滴，并可进一步凝结成冰。这些滞留良久的线形水和冰迹，会散射上方的太阳光，因此从下方观看时显得相当明亮。然而在较罕见的情况下，当太阳位于地平线附近时，飞机凝结尾会受到下方的阳光照耀。这些凝结尾向上投射的颀长影子，除非遇到高层云，否则通常隐不可见。而这正是本月稍早，在土耳其伊斯坦堡上空所看到的景观。地球各地都能见到飞机的凝结尾，当它们吸收红外光时，会让地球变暖，但高效率反射阳光时，却能让地球降温。这幅影像是一位颇为惊讶的摄影者，摄于上班的途中。
Your chat thread will be taken to the “Archived Chats” folder, which is displayed at the top of your chats. But that’s not what you want, so you’ll need to hide this folder from view as well. On your mobile device, long-tap on the “Archived Chats” folder and select the “Hide from Chat List” option at the bottom. If you’re using Telegram on your PC, right-click on the “Archive Chats” folder and select “Move to main menu.”
With Telegram, you can send messages, photos, videos and files of any type (doc, zip, mp3, etc), as well as create groups for up to 200,000 people or channels for broadcasting to unlimited audiences. You can write to your phone contacts and find people by their usernames. As a result, Telegram is like SMS and email combined — and can take care of all your personal or business messaging needs. In addition to this, we support end-to-end encrypted voice calls.
Telegram is a messaging app with a focus on speed and security, it’s super-fast, simple and free. You can use Telegram on all your devices at the same time — your messages sync seamlessly across any number of your phones, tablets or computers.
Telegram is for everyone who wants fast and reliable messaging and calls. Business users and small teams may like the large groups, usernames, desktop apps and powerful file sharing options. You can appoint admins with advanced tools to help these communities prosper in peace. Public groups can be joined by anyone and are powerful platforms for discussions and collecting feedback.In case you're more into pictures, Telegram has animated gif search, a state of the art photo editor, and an open sticker platform (find some cool stickers here or here). What's more, there is no need to worry about disk space on your device. With Telegram's cloud support and cache management options, Telegram can take up nearly zero space on your phone.
Unlike WhatsApp, Telegram is a cloud-based messenger with seamless sync. As a result, you can access your messages from several devices at once, including tablets and computers, and share an unlimited number of photos, videos and files (doc, zip, mp3, etc.) of up to 2 GB each. And if you don't want to store all that data on your device, you can always keep it in the cloud.Thanks to our multi-data center infrastructure and encryption, Telegram is faster and way more secure. On top of that, Telegram is free and will stay free — no ads, no subscription fees, forever.
Yes! Voice calls are currently available to users around the world.
Many modern travelers appear to struggle with managing various aspects of their finances simultaneously while abroad, such as banking, budgeting, investing, trading, and saving. It is important to have apps installed on the device that will help you carry out these necessary tasks.
Hot Topic in US